Acquisition
Q: How long does it take to get a single image result for you?
I can only give a vague answer to that, because it depends on the target I shoot and the way I shoot it. A typical LRGB image shot from my “The King” configuration takes me from starting of my set up procedure, to finish capture, integration and post-processing to the final result easily around 12h. If I shoot multi night exposures to get more total integration time the time scales up of course, because I have to set up and tear down twice and probably drive to a location as well.
Q: What are your typical exposure and total integration times?
My typical exposure times for my Nikon D5100 DSLR are 60s to 2 minutes. I calculated those values using a specific formula, which I will share in an article along with the explanation how it works. With my Atik 383L+ it depends on the filter I use. With LRGB filters I typically aim between 3 and 5 minutes per exposure, with narrowband H-Alpha, OIII and SII I aim for between 5 and 15 minutes. My longest exposure time so far was with Westerhout 5, where I took several hours of 15 minute exposures. Regarding total integration time I aim for at least 3h of data before I call it quits.
Q: How long does it take for you to set up your equipment?
The set up alone goes relatively fast for me, since I don’t disconnect cables and leave the cameras inside the telescopes. I also keep my telescopes together, so I just have to set up and level the mount and plop the OTA on it, mount the mount PC and connect everything. From there I need to run my software, polar align, focus and frame the target I want to shoot that night. I expect usually around 45 minutes to an hour of set up time, depending on how dark it is. If I can’t see Polaris I cannot polar align, which makes things rather tedious.
Q: How dark have the skies to be to capture good Astro images?
Well, most of my images I have shot come from a relatively bright place, technically it’s a Bortle 5 zone edging into Bortle 6, since I had a rather large city nearby. Read up about the Bortle scale here. I would say a Bortle 5 zone is more than fine to capture good and detailed images, but as always, you want to go as low as possible – and reasonable. That being said, all great Bortles won’t help you if the moon is up. So, don’t shoot with the moon up – except if you shoot narrowband. Otherwise, forget it. To find out your approximate local Bortle you can use https://www.lightpollutionmap.info/ with ATLAS 2015 data selected.
Q: Why do you have no planetary images?
It’s easy, I don’t really have the equipment to take good planetary shots. Compared to DSO objects planetary images need wildly different equipment – very long focal lengths and cameras with tiny sensors which shoot extremely fast videos. I have neither, so I don’t really have planetary images. This might change soon, though.
Q: How do you find and keep track of targets?
Since I got my motorized EQ6-R I just use Stellarium and StellariumScope to pinpoint and frame targets, By the press of a button the mount slews to that approximate position. Then I let the camera shoot and plate solve the actual position in the sky, which leads to the mount repositioning itself exactly over the target I want to shoot with an accuracy below 1 arcminute. The tracking part is handled by the motorized mount itself, since with polar alignment and it following the sky the mount will always keep the target on point. I also utilize guiding to increase the accuracy by a lot.
Q: How do you decide what you want to shoot?
That’s a difficult question and it really depends on how much time I had before to decide for a framing and target. It also depends on the current sky conditions (narrowband vs. LRGB) and the current targets in the sky. I try to shoot targets which will “move” near or over the zenith during the astro darkness phase of the night, where naturally the least light shines upon the sky.
Gear
Q: What is the easiest way to get started with Astrophotography?
The easiest way is to get a cheap and used DSLR or Mirrorless camera and a tripod, find the milky way and shoot away. I have an article up about Equipment Tiers and also Equipment Suggestions.
Q: How high is the cost to get a proper Astrophotography setup?
If you want to go motorized with go-to functionality, assuming with a DSLR, and you have no equipment at all, you can calculate with at least 2000€. You will need a motorized mount with enough capacity, a battery, a camera and a telescope. Don’t skimp on the mount, since it’s the most important part of your equipment next to the optics. Check out the Equipment Suggestions article to get you started.
Q: What makes a good Astro lens?
There’s one thing that is important for all optic elements and that is a full illuminated field free of chromatic aberration and field curvature. For lenses, that becomes really expensive really quick, for telescopes there are ways to reach at least the flat field part utilizing flatteners or coma correctors. Expect a longer article some time in the near future, but for now let me try to answer it in a simple way.
Generally you have to ask yourself if you go motorized or not. If you don’t go motorized you want a fast lens with a large FOV, that means essentially, that you want a very wide lens. Something like 18mm with f/2 would be ideal, but also very expensive – the not so expensive lenses have an issue with chromatic aberrations or other coma or astigmatism issues. Essentially the wider you go the longer you can expose without major star trails and the faster the lens is the more light and thus detail you will capture.
If you actually go motorized then the speed of the lens or telescope becomes less of an issue because you can just expose for longer to get the same light gathering as with a fast lens. You can also go way higher focal lengths, which mostly depends on the quality of your mount. Regarding the speed of the lens – or telescope – you have to consider that most telescopes are F/4 and up, where F/4 is actually considered very fast already.
Q: What equipment do I need for Planetary, DSO or Widefield imaging?
This is a good time to read up my article series Starting with Astrophotography. Nevertheless, for a too long;didn’t read here’s a summary:
Planetary: a telescope with a long focal length, like a Schmidt-Cassegrain Telescope, with a quality barlow lens and a planetary camera which is able to capture at very high speeds. Newtons also work. A motorized mount is not a must, but can be helpful to keep the object in the field of view of the camera.
DSO: a telescope or long focal length lens starting from 400mm and upwards, depending on the size of the object you want to image. You can work with a DSLR but a monochrome CMOS or CCD will provide better results (albeit with more effort). A motorized mount is a must since you really need it with those focal lengths. Guiding the mount is almost essential as well, except if you actually buy a mount in the price range of 10000€ and upwards.
Widefield: a lens with 135mm or lower is required to do “widefield”, typically done with a DSLR or Mirrorless camera. Monochrome CMOS or CCDs will work as well, but are not a necessity. A motorized mount is not a must, but can be helpful if shooting with longer focal lengths. Guiding is not necessary, but can increase the exposure time beyond the mounts capabilities.
Q: Can doublets be Apos, too?
Yes.
Processing
Q: What software do you use and recommend for capture/stacking/processing?
Capture: I exclusively use NINA for capturing my images and I would recommend you to give it a shot as well. It’s a simple to use open source software, where I happen to develop it as well. There are other solutions like APT or SGP, both of which cost money though and the UI is horrible to use.
Stacking: DeepSkyStacker works, PixInsight works as well. For Planetary there is AutoStakkert!3. If you don’t want to spend money on PixInsight yet, use DeepSkyStacker.
Processing: Honestly, there is only one software I can really recommend and that is PixInsight. I’ve seen adequate results with Photoshop too, but nothing comes really close to PixInsight. It’s expensive, yes. But absolutely worth the money. My image quality increased by a lot.
Q: Why don’t you use Photoshop to process your images?
As stated before, PixInsight is my one tool that covers most of my Astro processing. It offers the most flexibility and a lot of very good denoising and sharpening algorithms. There are also scripts to annotate, adjust colors or extract even very hard to get background gradients. It’s hard to process something in Photoshop once you actually got in the PixInsight workflow. I can recommend testing it out since there is a 45 day trial on their website.
Q: How long does it take you to process an image?
That really depends, usually at least 2h. If I’m not happy with the result of various processes it can take way longer. I had images I reprocessed and reprocessed ending up with easily 12h of processing time.
General
Q: How difficult is it to capture images in such high quality?
That’s a hard question. What is high quality? Really, I think the key to a proper result are good calibration frames (darks, bias, flats, especially flats) and good post-processing. Most images that come out of my stack are really underwhelming. I spend a lot of time in post to get a result that is stark in contrast but doesn’t fully blow apart the image.
Q: What is the difference between exposure time and integration time?
It’s relatively easy. An image is made out of several exposures which result in the total integration. So the integration time is the sum of all exposure times that went in the final image.
Q: How did you get into Astrophotography?
Oof, that’s a hard one. I was always fascinated by space and Sci-Fi in general. Always dreamed of taking a shot of the horse head nebula where you could see something. So I started to read up about the topic (when I had nothing to do). Then I just had to try out what I learned with a bad borrowed DSLR and was immediately hooked. Just try it out for yourself and see 😉
Q: If you had one thing you don’t like about Astrophotography, what would be it?
Honestly? The cold. I can deal with it, but it’s rather annoying. Especially in winter when it’s sub zero degrees and your hands freeze while you try to focus. That was one of the reasons I actually went with a mount PC. Now I can sit in my warm car while the mount is imaging. Or stay at home and still control everything.
Q: What is your favorite color?
Green. Shut up.