“Everything you do is cancelled…”
It’s been an unusual Spring to say the least. As I write this we are in week four or five of the “Global Pandemic” where businesses are mostly closed, churches are closed, restaurants and clubs are closed–anyplace where people gather is closed. So that means all my paying gigs are canceled for what looks like about two months. No stargazes for the Marriott three times a week or church live sound gigs. At least the golf courses are still open for when you really feel like hitting something!
The upshot of all of this is that there’s an unprecedented large block of time to fill and I can’t think of a better way to fill it than by trying to take my astrophotography to the next level since there are few things more time intensive than astrophotography! The problem was that the park where I’d usually go to shoot got closed about a week into this whole thing so I decided that I was going to find a way to work from home and go into a more “R & D” mode and learn a bunch of new stuff and not be too terribly concerned about getting images shot although that would be nice if it worked out.
Starting Easy
I didn’t really know if it was going to even be possible to take photos from my porch at the condo. There were a number of immediate challenges to consider: getting properly polar aligned when you can’t see the north star and all the light from everybody’s porch lights, passing cars and all that.
Last year I bought a 2nd telescope mount, a SkyWatcher EQ6-R Pro but never really put it through it’s paces as a photographic mount–mostly I wanted something that was a bit easier to move around but still quality for my public stargazes at the Marriotts.
Mounts used for photography are under software control so the first step was to see if the computers were properly configured to control it. After installing the “EQ Mod 5/6” drivers everything just popped up like magic; so far so good! I wanted it to not be stressed so I put my lightweight 4” refractor on there just to see what would happen.
Proof of concept: the 4” SkyWatcher refractor on the EQ6-R Pro shooting galaxy M90 (masquerading as M58).
Fine Align
In order to take long exposure photography of the sky one of the things you have to have absolutely right is getting your telescope mount turning in exact alignment with the Earth’s rotational axis, this is called getting “polar aligned” and is usually done by referencing the north star which is great if you can see it. However on my porch the north star is completely blocked so there’s another, much geekier, time consuming method called “drift alignment”.
This method is nothing new; astrophotographers have been using it for decades in the ‘pre-digital’ era. I’ve tried it a number of times in the past and I could never make it work. But now I had no choice so I started looking on YouTube for some expertise and found some videos that reminded me of an alignment tool that was built into my mount guiding software. So I had no choice but to give it a shot even though my history with this technique was steeped in failure!
Basically what it comes down to is that there are a couple of ‘special’ places in the sky where, if you point a telescope at a star there, turn off your tracking motor and watch what the star does, you can make successively finer adjustments to your mount’s aiming until the star doesn’t drift at all and you are polar aligned and ready to shoot. The software tracks the progress of the star for you and displays a red line that updates every few seconds and when it’s perfectly flat, you’re pretty close.
So I finally got it to work, I think. It takes an amazingly long time since you have to wait at least two minutes between adjustments and when you haven’t done it before you don’t have a handle on how much of an adjustment has how much of an effect. Right now it seems to take around an hour and a half to get it almost perfect but things are still loosey goosey enough that I don’t know if I need to spend even more time on it or I’m getting it as good as I’m likely to get. The one thing I do know is if I can see the north star I can use the PoleMaster camera I have and be aligned in less than 5 minutes! This is a good skill to have in my back pocket though and since I’ve got nothing but time right now I just have to suck it up and see if I can get this done in a reasonable amount of time moving forward.
Next Level Expectations
I was at the beginning of what turned out to be a stretch of five more or less clear nights in a row so now that the main technical hurdles were theoretically overcome with the SkyWatcher mount and scope I was anxious to try and see what would happen if I tried to take a real astrophoto with long exposures (60 seconds or more) over a period of a few hours while under control of the guiding computer.
Since the Virgo Cluster of galaxies was practically straight up I wanted to find a little cluster of spiral galaxies in there that would make a decent shot; I’ve decided that elliptical galaxies are too boring to look at to warrant the effort it takes. I chose M58 and ‘its neighbors’ as my first real target.
So how do you find something in the sky when you can’t actually look through your telescope except with a camera? Well first, since your mount is aligned already you can just go to the hand controller and type in the “M-5-8” and the mount will go there, sorta. The mount just counts motor pulses so you know that when you get there you’ll be in the general area but it’ll be a freakin’ miracle if what you’re looking for is dead center in the camera. So then what?
The Solution is in your Plate
In the last six months or so I’ve become aware of something called “Plate Solving” which is really geeky and cool. Basically you take a short exposure of the sky (10 seconds or so) and your computer compares that image to a library of images of the whole sky stored online or on your computer’s hard drive and when it detects a match it reports back that “you are here” in the sky, sends a position update to the mount and you nudge what you want to shoot into the best position in the camera frame. This is pretty freaking amazing when you consider that the plate solver has no idea how your camera is mounted or rotated on the scope so the stars could be in any orientation compared to the reference image. It’s even more amazing that you have your answer in a minute or less usually.
The ‘Cluster’ of Clusters
One of the things about the Virgo galaxy cluster is that you can pretty much just point your scope randomly anywhere in there, open up your shutter for a minute and there will be anywhere from three to fifty galaxies in your shot!
This happened to me on the M58 shot. It’s tough to see what you’ve got on a single preview shot–I knew there were a couple decent sized galaxies in there, both spiral and since I plate solved I assumed it was M58 close to the center… I didn’t find out until later as I was processing the stacked set of images that what I thought was M58 was really M90 and M58 was in the shot, but off to the side!
Nevertheless I had good skies, ran the auto focus routine (more on that later) and fired off sixty 90-second exposures, of which I was able to actually keep 47! Gotta love short focal length refractors. The guiding was only mediocre however but I couldn’t really tell if it was something about my new method of polar alignment that was sketchy or some other unknown factor like the tripod leg was sinking into the flower bed as the night progressed!
This relatively bland image is actually quite cool if you click on it to open in a larger ‘lightbox” environment. If you scroll around you can find 30 or 40 galaxies in here, all about 40 million light years away. Any fuzzy smudge of light you see that isn’t a small point of light like a star, is a galaxy with more than 100 billion stars in each for the most part.
Ratcheting up a notch
Since the initial night was generally very successful (Skywatcher mount now checked out for software control, local light pollution not really an issue as long as your scope is looking fairly high in the sky) I decided I would start using my ‘flagship equipment’: the Losmandy G-11 mount and new RASA scope.
The RASA 11-inch scope on the Losmandy G11 mount.
I was hoping that if I got things going early enough I could take a 2nd layer of pics of the Seagull Nebula over next to Orion. A couple weeks earlier I had shot a nice set of images of the Seagull with the H-alpha filter I have but it set into the trees before I could get the full-color image set so I thought this might be my chance. Turned out that getting the scope aligned was more frustrating than the previous night, never really got it exactly right and by the time I was ready to shoot the Seagull was getting pretty low in the west and the skyglow of Savannah and some approaching haze. I shot a bunch of images hoping that I could make something happen in processing but I ended up throwing them all away.
The RASA weighs 43 pounds on it’s own and with the guide scope, camera and other electronics it’s probably pushing 50 and the mount is rated for 60; I was hoping that this wouldn’t be too much of an issue. As it turns out the whole evening was a struggle and I wasn’t really sure why.
I did get one image of a super easy target that night although I had to throw away 65% of the images meaning that things are not as dialed in as they should be. Usually I can keep over 75%.
Here’s open star cluster M41, just a few degrees away from the bright star Sirius.
Open Star Cluster M41 in Canis Major
Emergency Observatory!
Earlier in the week I had gone out to my favorite park to shoot and discovered that all the parks were closed now! Damn!!! So I had to find a spot without too many lights in my face that was relatively open to the sky where it was ok to be for 6 hours or so. I remembered that the parking lot at the Port Royal golf courses seemed pretty wide open when I drove past there to do my Monday stargazes at The Barony Beach Club so I stopped in and received permission from the club manager to set up at the periphery of their parking lot.
Seagull Flies to the pinwheel
I thought I might have another stab at those Seagull nebula frames but by the time I was ready it was too low to get a decent shot–it’s pretty faint, even by nebula standards. So I decided it was time to shoot the Pinwheel Galaxy, M101, since it was going to be perfectly placed high in the sky for a long time.
I decided I was really going to do this right: take at least 1.5+ hours in color and 45 minutes of a layer in H-Alpha to make the hydrogen regions in the spiral arms look nice and pink. I got polar aligned, focused, and settled in for the long wait while the computer snapped away. I was able to keep fifty one of my seventy 90-second color exposures. I popped in the H-Alpha filter, refocused and shot 35 minutes until the Pinwheel spun into a tree. By this time is was 3am so I thought I’d call it an ‘early night’ and go home.
M 101 the “Pinwheel Galaxy”, up near the end of the handle of the Big Dipper. I’m happy how much detail I was able get even though I was using the RASA with it’s short focal length and wide field of view. The H-alpha layer turned out well too I think. Like the other wide field galaxy shots in this post there are a bunch of little ones hiding in there.
Tis the Season
Springtime is ‘galaxy season’ with the Virgo Cluster high in the sky and the galaxies around the Big Dipper also well positioned. Galaxies are very distant and therefore small in the telescope so I figured I’d make a big portion of my Covid19 induced research time oriented to getting my long focal length 10-inch Ritchey-Chretien Astrograph scope under much better control.
This scope has always been a problem for me–I bought it before I truly understood how rock-solid everything has to be with both your equipment and procedures to take decent photos with it. The tiniest little error and you’re not going to get the image you were hoping for. So I decided I would dive in and try and see what it would take to tame this beast since this long (2048mm) focal length scope is absolutely the best one that I own for taking galaxy shots. My wide field, short focal length scopes are much easier to control but unless you’re shooting the Andromeda Galaxy which takes up the whole frame because it’s so close, you end up throwing away three quarters of your image because a galaxy that’s 40 million light-years away only registers on a small group of pixels on your camera. Much better to zoom in and have that thing be as big as possible so you have more pixels to work with later.
So I got over to the storage unit and got this one out for the first time in months and set it up on my porch more or less.
After a number of configuration attempts, this is what I ended up with for the ten-inch.
More software now!
As you can see, there’s a lot going on electronically on a photographic telescope. You’ve got your main camera, guide camera, motorized focus control, temperature/humidity sensors, dew heater strips, power management box and a USB hub so a computer can talk to all of them.
Up until a month ago I had been using a nifty little box called an “ASI Air” which would manage all the USB traffic, guide the mount and store the photos on a usb stick but when the last firmware update came out it inexplicably just stopped working so while I’m sorting that out I needed something to take the pics with so I found out about a really great program that pretty much everybody who’s serious is using called Sequence Generator Pro. It had a 45 day fully functional free trial so why not?
This app is fantastic! You could run a whole observatory with it! It has control areas for observatory domes, the slit in the dome, weather monitors, filter wheels and a bunch of stuff I hadn’t even stopped to consider so I began digging into that and it’s really amazing what it can do. So I ran a USB cable into the house under the front door and set up my comp there.
Telescope & Imaging Control Center.
First thing was to get it talking to the mount, the main camera, guide camera, electronic focuser and dew heaters all of which happened without a problem.
He Gonna Focus?
One of the great things about having a motorized focuser on your scope is that you can focus without touching the telescope. Touching the scope makes it shake a little making it hard to focus since a shaking telescope has stars that look out of focus even if they aren’t. One of the bad things about motorized focus is you can’t just reach over there and tweak the focus–you have to use the motor. The motor was new to this scope so I spent about an hour manually figuring out how much travel there was according to the numbers it was putting out and roughly where focus was going to be for this particular setup.
One of the real benefits of the software controlled focuser is that the computer can run a routine to automatically focus your scope buy trying a series of focus positions and seeing which one is the best and then set it there. Focus can also change if there’s a significant drop in temperature, or if you switch filters so there is a temperature sensor that plugs into the focuser so you can say, “Refocus the scope every time the temp drops 1.5°C or I switch filters”. Amazing.
Well at least it sounded amazing, except I tried it several times that night just seeing what would happen and it failed every time! I figured that I would do some reading the next day since I really didn’t understand its process or what would be my best settings to type into the various values and sure enough I didn’t really have good settings typed in. Once I understood how it went about its business it was easy to get something together and it has been pretty reliable since then although I’ve noticed if you have some high clouds about it can kinda throw things askew as it’s taking its readings leading to a less than sure result.
It was worth the effort though because bad focus is the one sure thing that will ruin every astrophoto! And if your target is going to be 40 million light years away you better be spot on if you want to see any detail at all.
You gonna take a photo or just mess around all night?
Well by now it was well after midnight and I thought I’d see what I could shoot and check out how things were when I tried to take an actual photo with this beast. As it turned out, my polar alignment was not nearly good enough for long exposures and the 10 day old huge Moon in the sky was stomping on all the faint galaxies so I decided to just take a photo of it since I had some clouds rolling in anyway. I called it a successful night of R & D and was glad that I was able to sit inside my place and control things rather than travel to a park and set up just to walk away with only a moon shot.
The Moon on April 4th, 2020
Clear!
It was unusual to have this many clear nights in a row and by now the neighbors were stopping by to ask questions every night at dusk as I was dragging everything out and setting up for whatever was going to happen that night.
I felt like I might be within striking distance of a total solution with the R-C 10” scope so I was determined to spend as long as it took to get a polar alignment that was as solid as I could get it using the drift method. It took me over 2 hours but I thought I had something that was pretty solid so I chose as my target for the evening, galaxy M61 which is part of the Virgo Cluster but kinda south of the main group so that meant I wouldn’t have to worry about it moving behind my building like the higher up cluster members.
I shot almost 2 hours of 90-second shots and ended up having to throw away half of them. By this time I was wondering if I’d ever be able to take the 3-5 minute shots people I follow on YouTube were taking. But the 40 shots I got were pretty good and with the usual slavish processing in Photoshop I was able to come up with this:
M61, 40 million light-years away in Virgo. Click to open a larger version and see all the ‘bonus’ galaxies!
I closed out the night with something easy, another open star cluster: M48
M48 in the large, sinewy constellation of Hydra. I think this one would be better if you could see more of the empty space around the cluster but I wasn’t about to swap out the telescope at 5am!
Wearing the Sombrero, again…
Ok, I had tried and failed earlier in the week to get the Sombrero Galaxy, M104 but ended up taking 3 hours of unusably out of focus shots, perhaps due to temperature change or I don’t know what.
I shot the Sombrero last year as I was just starting to get some results doing this and while I was pretty happy with the image at the left at the time (this was back when any image at all was a huge victory) I realize I had learned a lot since 2019 and wanted to give this one another shot since at that time I could only take 15 second shots before the images were unusable and I only had 39 of those to work with!
This go ‘round I wanted to really get some good data on this thing so I shot 30 second exposures, about 240 of them hoping that my setup (which was getting better but still suspect) would allow me to keep most of the two hours of shooting. I had some clouds roll in at the end of the run and had to dump the last 20 images and with the still higher than usual attrition was only able to call 86 of them worthy of keeping. This was starting to get depressing…
Nevertheless I processed this image from start to finish not once but twice, finally ending up with something that is definitely better, but not as much as I was hoping.
M104, the Sombrero Galaxy in Virgo. Gotta love that lane of dust around the middle.
Take 2, Number 2
Even though I try and convince myself that I shouldn’t just keep shooting the “No. 1 Solid Gold Hits” over and over sometimes I don’t seem to be able to help myself which was the case last Sunday when I only had half a night to shoot from Sky Guy Porch Observatory. The benefit also is that you get to practice your image processing in the computer which is actually more responsible for what you see looking good as long as you have decent data to work with.
So I reshot galaxies M65 and M66 below the main part of Leo and part of the famous “Trio In Leo” along with galaxy NGC 3628 (not appearing in this film).
I’m much happier with these versions and put to good use some techniques I’ve developed to enhance detail in these distant light smudges. The editing also seems to give them a 3D effect somehow, not sure why but I’ll take it!
M65 (top) and M66; two thirds of the “Trio in Leo”. Click to open larger and check out the cool cloudy look on the bottom one.
Reverse Pinwheel?
One night while my early exposures were running I was on the computer looking for my next target and I ran across this gem: M83 “The Southern Pinwheel”. I can see why too as it was only just slightly skimming above the buildings across the street which would put it pretty low in the sky, all the way down in Centaurus constellation which is getting pretty low, even from South Carolina!
It’s a cool looking face-on spiral galaxy and I had some time to kill and was all set up so I just swung the scope over there, centered it up and without too much fanfare started shooting 30-second exposures until it disappeared into the condo roofs.
When it was all said and done I had only 32 usable exposures out of 58 taken for a total of 16 minutes. 16 minutes?!!! This is nowhere near enough data so I thought I would take those shots as a challenge to my image processing methods to see if there was any remote possibility. Working in my favor was that this thing was only 16 million light years away, less than half the distance to the main part of the Virgo Cluster so that meant it was relatively large on the camera sensor. It’s not a masterwork but came out better than I thought it would!
A lot of the knotty hydrogen regions in the spiral arms are clearly visible and you get a sense of the oblong nature of it which is a little unusual.
M83, “The Southern Pinwheel” in Centaurus. Click to see larger
One more and I’m out
Galaxies are not the only thing that are small in the sky and well suited for a long focal length telescope; you can also shoot Planetary Nebulas which are individual dying stars like our Sun.
There’s a fun one called “The Ghost of Jupiter” or “The CBS Eye” nebula hanging out in Hydra. After OD’ing on galaxies for two weeks it was interesting to shoot something that’s actually nearby and fairly bright!
NGC 3242, “The Ghost of Jupiter”
Speaking of Planets
We’ve got Jupiter, Saturn and Mars coming up about 4:30am these days and I’m doing some research on how to shoot these which is a completely different kind of astrophotography from the Deep Sky stuff I usually shoot.
We’ll see what I can get together…
Carpe Noctem from the Sky Guy Home Observatory, Covid19 edition.
Bill