Michael‘s Astrophoto Blog

One of the reasons for getting the Hyperstar optics for my C9 last year was the fact that objects like M42 are almost impossible to properly capture with a normal reducer or let alone at full focal length. Now with the winter almost over I noticed that somehow other projects were always taking precedence in the very few clear nights we had during the past moths.  So I started imaging M42 using the Optolog L-eXtreme while the Moon was still out. Luckily I was able to add more frames without Moon getting to almost 10.5h total exposure time. In processing I tried to find a compromise between showing the structure of M42 itself and the surrounding nebulosity. The next object I started imaging, again with the Hyperstar and the Optolong L.eXtreme filter, was the Seagull Nebula. If you want to show the beautiful Seagull features of this nebula it is a slightly bigger object, so I had to compile it as a mosaic. Each mosaic tile has 5h exposure time (150x2mins). IC2177 - Seagull Nebula The ...

I had been hoping to photograph the new comet all month, but the January weather had not been very accommodating. I was able to get a few glimpses at the object on January 20/21, which got me even more  excited about the object and off course there was some hype about the "green comet" in the media.  Finally on January 29th we had one (single) night of (reasonably) clear weather and after battling through some technical issues getting the comet properly framed and tracked I was able to shoot a number of frames. This first image contains the data from all the reasonably goof frames I was able to take that night. Comet C/2022 E3 (ZTF) on January 29th approx 400x30sec on C9 Hyperstar The other thing I noticed, when blinking through the individual frames one could see quite some movement in the comet's tail during the night. Evolution of comet's tail throughout the night of Jan29 This image shows this rapid development of the comet's tail.  At the beginning the tail w...

The Horsehead Nebula is almost a mandatory mandatory object to capture with every new optics. I was eager to see how the Hyperstar world do with it. Unfortunately weather and moon were not quite supportive of this plan. As even thin clouds lead to huge halos around the bright star(s) I had to discard quite a number of frames. Luckily over Christmas it was possible to collect a decent amount of data in reasonable quality. IC434 the Horsehead Nebula 152x60sec, C9 Hyperstar, ASI294Pro IC443 the Jellyfish Nebula is quite a beautiful object. However, the original frame I chose contained two relatively bright stars and the Optolong filter is creating a gigantic halo around them - one was even able to the cabling of the Hyperstar within the halo. My PixInsight craftsmanship proved insufficient to fully fix that, so I tried to tame one of the halos and cropped the image to remove the 2nd one. IC443 Jellyfish Nebula 117x120sec, C9 Hyperstar, Optolog L-eXtreme, ASI294Pro Shot at the same nig...

Weather conditions had been pretty mediocre over the last couple of weeks. In addition to the almost full moon clouds kept moving though, so a majority of the frames I took were unusable. It really felt more like "lucky imaging" than a regular session of deep sky photography. I did a more thorough analysis of the raw frames and noticed that the presence of the Moon has quite an impact on the image quality, even for narrowband pictures. However, I noticed as well that apparently the final images still are benefiting from including the frames with poor signal to noise ratio (eg. due to thin clouds moving through). In the following images I included all the frames, where the nebula was at least visible, even if they had a poor SNR. I guess this approach of imaging at almost full moon at poor weather will not be viable for fainter objects, but I think the results show that it may be still worth it for the brighter nebulae. I am never sure if I like the natural colors or the HOO p...

When I started with astrophotography last year I exclusively worked with free software for the post processing tasks. I mostly used SIRIL and a little bit of Gimp as tools. Some of the early results I have shared in this blog. They were ok at the time, but I knew that I wanted them to become better in the long run. So early this year, during galaxy season, I was starting to search for the software environment I would be using during my next steps. In principle the free tools can be used to produce extraordinary results much beyond what I was doing at the time. However, I felt that there may be limitations at some point and apparently most astrophotographers are switching to other tools eventually. As a result of that there is very little information available about how to use the free tools specifically in astrophotography beyond the very basic tasks.  I tested a few solutions, but eventually decided for PixInsight, apparently a pretty large number of astrophotographers are using t...

The comparably short focal length of 525mm provided by the Hyperstar is giving a quite big field of view enabling the fast imaging of objects that are simply too big for the optics I was using before. The C9.25 has a focal length of 1480mm with reducer and 2350mm at primary focus. This is good for smaller objects like most galaxies, but most of the objects I showed in the previous posts simply wouldn't fit in one picture.  I was eager to take picture of all the big objects that I always took off the list before. However, as it turns out, there are still a number of "famous" objects that won't fit in a single image even with the Hyperstar. So, I did bite the bullet and started composing mosaics of multiple images. It turns out that this works quite well, even though the required exposure times grow quite fast with the number of mosaic panels. Here is a first 2x2 mosaic I did of the North America and Pelican Nebula. Each subimage is an integration of 200 frames. My seco...

Last week we had two clear nights. Even though it still was some 25-20% waning moon I decided to image full RGB spectrum - without the narrowband filter.  Many experienced astrophotographers will concentrate on the same object over multiple nights to gather data for very deep images. However, somehow I have not developed that level of maturity yet. I wanted to play and to see what my new Hyperstar optics is able to do. So, I took pictures of a number of nebulae to get a better sense of what could be nice targets for the future. As I had already taken a picture of the "Heart Nebula" I added the nearby "Soul Nebula" as well: The Elephant trunk nebula is a pretty big (and beautiful) object. This is my first image of it. I noticed that the actual "trunk" is relatively small, so it may be worth imaging at a longer focal length. The Cave Nebula an interesting object with many dark nebulosity - fits quite nicely in the Hyperstar frame. The Bubble Nebula is actual...

One of the main open questions when buying a Hyperstar was how it would work with L-eXtreme dual narrowband filter. At f/2.2 the light will no longer be mostly parallel to the optical axis,but will pass the filter at comparably high angles. This will lead to a downward shift in the filter transmission wavelengths. There are filters that are specifically designed to compensate, others just have wider transmission windows to be less sensitive for that effect. However, as these filters aren’t cheap, I wanted to see what I can do with my L-eXxtreme first. Results published by other amateur astronomers vary from "the filter is completely useless at f/2" to "among my many filters the L-eXtreme is the best with my Hyperstar". Apparently, there is a bit of variability in the spectral transmission curve between the individual filter specimens. In my second night of testing the Hyperstar I therefore took a number of images using the filter. As there was rain forecasted in the...

One of the first images taken with my new Hyperstar.  After long deliberation I bought a Hyperstar system for my C9.25 Schmidt Cassegrain. For quite a while I was torn between the Hyperstar and getting a separate refractor. I did a lot of research and in the end I changed my opinion almost on a daily basis. Finally, I decided that the pros and cons of these two approaches are probably reasonably balanced and that I need to try it myself.   If you are not familiar with it - the Hyperstar is an optical system that is put in place of the secondary mirror of a Celestron Schmidt Cassegrain telescope, basically turning it into a very fast astrograph. For example, C9.25 becomes an f/2.2 system with 525mm focal length. The Hyperstar mounted on top of the telescope  Rough Collimation One of the drawbacks of a system like the Hyperstar is that, like all reflector telescopes, it requires some level of alignment i.e collimation of the optical components in order to perform optimally....

Moonless nights are great for imaging without the filter. While I enjoy using my narrowband filter to capture images of faint nebulae, not all objects are really suitable for it and sometimes I just like the unfiltered view.     Therefore I try to take unfiltered pictures whenever the conditions are right.   The other week I took a number of pictures of nebulae at full C9 focal length of 2350mm. As the objects were within or close to the plane of the Milky Way the pictures had many stars that were quite a distraction from the main object. This hardly a problem when using a narrowband filter, as only a small percentage of the star light is getting through. In unfiltered images number, brightness and size of stars can become an issue. Conditions were probably not perfect, increasing the problem. However, at these long focal lengths the effect is hard to avoid entirely.  One can address this in image processing by various star reduction algorithms. I took a quick crash ...