Category Archives: Star Clusters

The Rosette Nebula

Rosette Nebula on Jan 25, 2020. 67×30 sec, Gain 42, Offset 25, -20C, UHC-S filter, QHY183c, Televue TV-85 at F/5.6, Atlas EQ-G w/EQMOD.

I was surprised how well this came out with only about an hour of data.  I was after galaxies this night and I only took this to kill time.  Even the 33 minutes worth I posted initially looked half-decent.   I will have to devote a session to this one and possibly use the L-eNhance filter instead of the UHC-S.

Saturday-Sunday Night, Dec 7th-8th, 2019

The Moon. 5 frames stacked in SharpCap 3.2 LiveStacking. QHY183c, L-eNhance, TV-85 at F/5.6.
The Ghost Nebula and Gamma Cass. QHY183c, 125 x 30 sec, Gain 42, Offset 42, -20C, L-eNhance filter, TV-85 at F/5.6.
NGC7822 and Ced 214. QHY183c, 122 x 30 sec, Gain 42, Offset 42, -20C, L-eNhance filter, TV-85 at F/5.6.
The Cone Nebula. QHY183c, 193 x 30 sec, Gain 42, Offset 42, -20C, L-eNhance filter, TV-85 at F/5.6.
M46 and NGC 2438. QHY183c, 18 x 30 sec, Gain 42, Offset 42, -20C, L-eNhance filter, TV-85 at F/5.6.
Leo Trio. QHY183c, 120 x 30 sec, Gain 42, Offset 42, -20C, L-eNhance filter, TV-85 at F/5.6.

Six images bagged in one night, although a few need at least another nights worth of additional time. Big city light pollution was circumvented with an Optolong L-eNhance filter.

30 second sub-images for the DSO’s. The moon was 5 frames stacked in SharpCap 3.2. The Cone Nebula has 130 subs from last night and 63 from a previous session. I also shot M51, but it was only a few frames before twilight and was not really enough for a display image.

The Bubble Nebula

The Bubble Nebula. 120×30 and another 1800 sec mixed exposures. QHY183c, L-eNhance Filter, TV-85 at F/5.6.

A mixture of 120×30 sec exposures taken with a L-eNhance filter and a mixture of 15, 30 and 1 minute exposures taken with a UHC filter.   About an hour and 30 minutes total.  The 120×30 set was at 30 gain and -20C.

I am starting to like  the 30 gain setting, since it gives the best results with shorter exposures.  Over 40 is too much noise and under 30 it is just too slow.

When the set began there was no matching dark to subtract, so I was using one at gain 20.   I stopped after about 10 shots and took some darks and then restarted shooting.   I’m glad I did since the amp glow was starting to show up bad on the right side of the frame.  The new darks overcame it and the glow averaged out after a while of LiveStacking with ShapCap 3.2.

Veil and Cave Nebulae: L-eNhance Filter Test

West Veil Nebula. 46×30 sec, QHY183c @ -15C, Gain 42, Offset 100, L-eNhance filter, Televue TV-85 at F/5.6.
The Cave Nebula. 26×240 sec, QHY183c @ -15C,, Gain 20, Offset 31, L-eNhance Filter, Televue TV-85 at F/5.6.

What luck!  First light for new filter is the day I received it!   Thanks to the clouds for staying away.   What I wanted to test was my new Optolong L-eNhance dual-band nebula filter, which is similar to the UHC filter I already own but with a narrower bandwidth and a more even color rendition across the frame than the cheap UHC one I’ve been using.  I got to try it out before the  run of good weather we’ve been having ended.

I was a able to test it on the Veil, which I recently imaged, and the Cave Nebula, which I had never shot before.  I am very pleased with the results.   Even color and illumination and better rejection of LP.

The Veil nebula was shot like I’ve been doing – 30 sec sub images at high gain. The Cave was long exposures of 4 minutes and I managed to get 26 subs.  The Veil is a finished image and the Cave Nebula is still a work in progress.   It seems the long exposure, 4 minute darks I used were not too good of a match and there are numerous hot pixel trails left to manually repair or clone out still left to do.

I also tried it on two reflection nebulae, one being the Running Man in the image below, and it was not as good as my UHC filter.    I also tried one star cluster, M35, and it is the last image below.  No galaxies yet, so I’m not sure how well it will work for those.   Maybe next time I will have to try for one and find out.

M42 – 114×30 sec, QHY183c @ -15C, Gain 42, Offset 42, L-eNhance filter, Televue TV-85 at F/5.6.
M35 – 20×30 sec, QHY183c @ -15C, Gain 42, Offset 42, L-eNhance filter, Televue TV-85 at F/5.6.


Test of Canon 200mm F/2.8 Telephoto with QHY183c Camera

M45, The Pleiades. 56×30 sec, QHY183c, Gain 20, Offset 31, -15C, Canon 200mm F/2.8.
The North American Nebula. 167×30 sec, QHY183c, Gain 2, Offset 31, -15C, Canon 200mm F/2.8.
The Horse Head Nebula Region. 8×120 sec, QHY183c, UHC Filter, Gain 20, Offset 31, -23C, Canon 200mm F/2.8.

I bought the adapters needed to mate my new QHY183c camera to my Canon lenses.   I tried it out with the 200mm F/2.8 telephoto.   No way to control the F-stop diaphragm, since it needs a Canon camera to do that, so I had to shoot with it wide open.  BTW, this was from the light polluted metro area I’ve been shooting from lately.

Since this is one of the cheaper lines of Canon lenses, it suffers from optical imperfections like astigmatism.   That makes the red focus to a line up and down and blue and green focus to a line left to right.   It really messes up the star shapes and there is no way to fix it except to stop the lens down to F/3.5 or higher.   Oh, well…