riklaunim

If you stretch a lot / stack a lot without a good dark frame it can show up. I have a different camera with IMX 432 and its amp glow is like this just shifted more to the bottom part

Images were made with an Omegon veTEC 432 M camera (IMX 439, 9um pixels), Bresser 200/800 f/4 Newtonian, and Explore Scientific Coma Corrector.

Around 20 x 120s frames were stacked for each image. Flat/dark, Graxpert to limit gradients aside from some weird reflection-like ones...

Theory and details on https://rkblog.dev/posts/astronomy/m27-nebula-in-various-bands/

CLS-HSI (LRGB type image):

H-alpha/IR/CLS: IR on green will show stars hidden by dust or emission from the nebula (check how some stars are brighter here than above):

H-alpha / Neutral oxygen 630nm / [He II] 587nm:

Some nebulae can realistically use [O I] and [He II] emission lines for imaging although they won't be as bright as the more popular ones and require custom filters.

The infrared wider band can be handy more often to go through the dust in a wider range of nebulae.

Channel shots:

Astronomik CLS-CCD:

Baader [O III] standard filter:

Baader H-alpha standard filter:

Optolong [S II]:

Astronomik ProPlanet 807 - infrared, skipping all major emission lines as well as going through dust more easily:

[He II] custom filter with halo from either light pollution or the filter itself (same wavelengths as sodium lamps):

[O I] neutral oxygen 630nm:

Astrodon UVenus:

Old SCT C11 images:

[O I]:

[He II]:

Bresser 200/800, Explore Scientific coma corrector, Omegon camera, Baader Neodymium 2" filter, around 100 x 60s frames. Focus is almost there and some reflections sadly went in as well even after some gradient removal (Graxpert):

I do have street lights from bottom left/right angles (and some bandpass filters don't have such issues) so I'm guessing it's hitting the inner OTA wall and reflecting to some extent.

And before M33 was in the field of view I did shoot M15, which looks way better (although at the 60s the core was already a bit overexposed):

My f/19 DK14 got upgraded by my friend (who made the scope in the first place) to have a much better primary mirror holder and now it seems to hold the mirror properly, no weird ghost edge on the Moon and so on... although still now sure if it's that sharp (and I still have to move secondary bit closer to have enough backfocus for ADC and filter wheel)...

QHY174MM, Orange IR-longpass:

And as the seeing looked really good, a bit of over-scale with 2x Barlow on top of it:

And few Moon shots:

5 hours ago, matt_baker said:

I've heard things like wrapping it in Reflectix to slow down the cooling to prevent heat plumes which is something I might consider. Also the idea of using a Lymax cooler but I do wonder how much better that would be considering the cost.

Has anyone got any recommendations or tips to help?

Depending how fast the temperature is rising/falling C14 may not be able to follow it - thus never reaching ambient and always having air current/boundary layer around the primary mirror.

With all SCTs I had, and especially C14 I used an active fan to push air through the whole OTA so when I started using it it was forced at ambient - but if the temperature change was to steep then around 40-60 minutes and it would start to drag again.

As for collimation you can start with looking visually to see if the error is large or what's the thermal state of the telescope.

Self-made is likely not an option Not that skilled nor a 3D printer.

3 minutes ago, wimvb said:

Remember that NASA’s IR imaging telescope pre JWST was airborne, to exclude most of atmospheric influences.

Depends how long wavelength you want. 1100-1600 nm is often done from standard ground observatories.

Silicon sensors stop responding to wavelengths longer than 1100nm. This isn't that much of infrared (more like "200% red"). Some time ago Sony did release a different sensor that operates above 1000nm but the price is similar to a small house.

Also on longer wavelengths light can go through dust more easily, which is visible even with standard sensors (Ha filters vs PP742):

Anyone here used Alpy 600 or something similar? I'm looking into slit based spectroscopes and I don't see much options (sanely priced). I used Star Analyser before and now I want something with a slit to target nebulae but also planets, like specific features in Jupiter atmosphere or like sodium emission around Io and so on (and comets if they show up).

Nice, good to see more effort into this... although they did get beaten out of the market I guess to make it a constant meaningful revenue.

Now to do some pull requests, maybe sort cameras list ASCOM vs rest of the world etc

RedCat 51, Omegon veTEC 432 M (9um pixel, 1600x1100), Svbony UHC, 180s exposures (around 30 frames for Pleiades and around 60 on the horse).

1 hour ago, FrankRyanJr said:

I'm convinced it'll be a super scope for Planetary / Lunar visual but also Imaging. 

Can't say about visual but for imaging it's just 6". Depends what quality you are expecting. Good resolution starts around 8" and then going up. For imaging it's  all about aperture.

11 hours ago, vlaiv said:

Hope you don't mind - I took liberty to process the fits you posted, here is result:

That's why I posted the raw stack Nicely done.

Did a simple "experiment" of collecting 1700 frames at 30 sec over few nights for M5 (RedCat 51, ASI178MM, UHC filter) to see how much background I can get out of it and what's the noise will be like. Sadly not that much magic detail there, but at least it does look nice

FITS file: https://www.dropbox.com/s/9fzjw8ewo3n1m76/base.fit.zip?dl=0

bin2:

bin1: link

On 13/11/2020 at 13:12, Astrid said:

was wondering, is there a webcam that could get me good results for DSO AP?

Actual webcams no as they don't support longer exposures nor good image quality. There are some cheap entry level dedicated cameras like some QHY/ZWO/Svbony models and that's better used with a lens or very short focal length APO refractor. 8" Newtonian will give a very small field of view (only DSLR for that) plus small pixels of such cams don't help either (quite quickly you will run into guiding problems for 8" telescope - requiring guide setup and way more precise mount setup assuming it can track well). Even if you are getting a DSLR - try imaging with like a 100 mm lens first (all attached to the EQ mount, no telescope) - that's way less sensitive to tracking errors.

I've made some benchmarks of few popular astro processing apps (Nebulosity, PIPP, Autostakkert) and you can see the results on:

https://rk.edu.pl/en/benchmarking-astro-processing-apps/

It turns out some apps do like lower latency of Intel systems while storage speed does matter as you could expect. For some processing NVMe SSD or a Ramdisk is the fastest.

We have Jupiter on the night sky, Moon shows up from time to time as well. Let's try to do some more "exotic" type of imaging of those objects:

* Io/Jupiter sulfur torus and sodium clouds that can be photographed with the help of [S II] DS filter or a custom narrowband filter centered around 589nm for sodium. Io or the whole Jupiter in the field of view recommended, lower resolution than when doing normal imaging
* Lunar petrographic imaging showcasing surface age and composition. Requires 5 wide bandpass filters, mostly in IR
* And as a side note 630 nm "neutral oxygen" filter for some nebulae as well as comets. 589nm sodium filter can also be used for 587 nm He I nebulae emission or with Baader AstroSolar to watch a yellow Sun instead of a green one with Solar Continuum

More details at https://rk.edu.pl/en/different-ways-photograph-jupiter-moon-or-nebulae/
Custom filters can be found in stores like Thorlabs, Edmund Optics but also Chroma that provides astronomical and other filters. Aside of that ebay stores like Bjomejag.

Tried Jupiter and Saturn this "morning", got to bright for Mars sadly, although imaging low over horizon isn't that promising either. 14" DK, ASI178MM, ProPlanet 742:

And a very quick daylight test with a stand-alone microscope camera (HDMI, can record clips):

This one was without ADC (tried it with ASI camera but even with nearly max setting some dispersion was still there). The camera has very small pixels and even with downscaling it does it's bit to big but still, could be handy as a stand-alike option (still have to test exposure control as it's auto with some offset options).

Like a week ago I've tried to test RedCat51 and ToupTek ATR3-16000-KPA color camera. Strangely enough guide camera could not pick up any guide stars (got defocused somehow or camera playing tricks) so had to go with 30 sec exposures times 190 with Baader Neodynium as LP filter.

Started imaging like a week ago but due to weather or Moon could not finish it, only 20 frames (60s if I recall correctly), Svbony UHC, RedCat 51, ToupTek ATR3-16000 color camera.

Full frame: link

2 x bin2:

Crop on Hubble's Variable Nebula

Venus show around 17:24 local time through few filters, only UV give any clear details. ASI178MM, 14" DK f/19.

1000nm longpass:

Astrodon UVenus:

UV-IR,IR,UV (UV as luminance to add contrast.. and noise):

bin2:

I've picked up a 60 mm Mak on a sale from Astroshop in like December and managed to do some testing, viewing with it. It's likely just a SkyWatcher rebrand but SW seems to not really offer less than 90mm Maks that often. At 77 EUR the price is very low for a telescope and it works - at low magnification you can see somewhat small but sharp Moon. On the other hand I had to collimate it and had some problems getting the correct defocused star image - and thus good quality of higher magnification views.

For daytime use, as a finderscope for a bigger telescope or maybe even a guidescope it could work...

Full review on my site: https://rk.edu.pl/en/mightmak-60-small-and-cheap-maksutov-telescope/

Raw Rosette stack: https://www.dropbox.com/s/07f5uj4azl9z4h7/roz.fit.zip?dl=0

Gradient removed in IRIS:

It's somewhat in a big city, but on the edge and having only some buildings and then forests. I rarely had gradients, few times used IRIS to remove it, but that was with mono and CLS or narrowband filters The local neighborhood street lights are slightly below my balcony and they do glow directly quite a lot. That could be the more direct cause depending on sky region. With H-alpha filter I was able to catch Simeis 147 so the sky can't be that bad

Got a break in the clouds so I've managed to get few more test shots from the new set - RedCat 51,ToupTek ATR3-16000 color camera, Baader Neodynium as the LP filter.

20 x 180s, even it's high in the sky still have some gradient:

Rosette nebula was super hard to see. The stars were there but nebulosity became visible only at longer exposures (where as with mono camera and CLS or narrowband filter it was "detectable" even on ~sec exposures):

The gradient is strong, I have to remove it as there is way more signal there:

It's like one of the street lights below my balcony somehow directly reflecting of the telescope inner walls etc.