DeepSkyHosting

Triplet in the constellation Leo

malex
56803
Category:Deep Sky
Published:
2620
Triplet in the constellation LeoIC 2686IC 2693IC 2696IC 2697IC 2710IC 2711IC 2726IC 2728IC 2731IC 2733IC 2755IC 2772IC 2773NGC 3623NGC 3627NGC 3628IC 2684IC 2689IC 2690IC 2694IC 2695IC 2708IC 2722IC 2725IC 2729IC 2745IC 2762IC 2763IC 2766IC 2767IC 2776IC 2779IC 2782IC 2784IC 2785IC 2786IC 2787IC 2788IC 2791
Resolution:
1817x1308 px
File size:
13651 KB

Photo description / processing

Captured an additional 3 hours in the red channel. Consequently, 3 hours were added to the synthetic luminance channel. Scale 70%.

Technical information

Telescope/Lens
Объктив Юпитер 21М
Camera
ZWO ASI 178 mm
Mount
Sky-Watcher EQ3-2 MyDrive
Guide Scope
Юпитер 37А
Guide Camera
QHY 5
Accessories
Фильтр Baader Planetarium NEODYMIUM 1.25", ССD-фильтры NoNaMe
Software
Maxim DL, DeepSkyStacker, FitSracker, PS
Location
Kharkiv, Ukraine

Light pollution

Orange, Bortle 6 zone

astroscope.ua/viewtopic.php?f=8&t=11716&start=560#p67240

Exposure

  • 18 × 300″ · ISO/Gain: 190
  • 30 × 360″ · ISO/Gain: 190
  • 20 × 360″ · ISO/Gain: 190
  • 27 × 360″ · ISO/Gain: 190

Total exposure: 9 h 12 m

Photo versions

Triplet in the constellation Leo
Current photoUpdated
Triplet in the constellation Leo

Mar 28th, 2020

9 h 12 m

Captured an additional 3 hours in the red channel. Consequently, 3 hours were added to the synthetic luminance channel. Scale 70%.

Triplet in the constellation Leo
Triplet in the constellation Leo

Mar 24th, 2020

1 h 30 m

Jupiter 21M test. It seems like the light grasp has improved, judging by the lettuce leaves in the Hamburger. The detail also seems higher. But the overall impression of the lens is just okay. It still doesn't have the same sharpness as the Jupiter 37A. The aperture was stopped down to f/5.

Triplet in the constellation Leo
Triplet in the constellation Leo

Mar 21st, 2020

1 h 12 m

Today's trio. (March 20, 2020, or rather yesterday's already :)) ) Aperture stopped down to f/5. Yes. Aperture rules. The previous shot had 120-second exposures, lower gain, but higher transparency. Although the total integration was different. Maybe it's precisely about the integration time. But it seems that stopping down the aperture also reduced the resolution. I'll try switching to the Jupiter-21M lens. I'll stop it down to f/5 and get the aperture of a Jupiter-37, but at a fully open aperture. We'll see.

Triplet in the constellation Leo
Triplet in the constellation Leo

Jan 19th, 2020

3 h 18 m

A trio of galaxies in the constellation Leo and neighbors. Imaging from January 8th and 17th, 2020. Scale 70%. Seems slightly out of focus.

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Comments

malex
If you're referring to the rays in the upper right corner, then no. The darks and biases are original. But this glow still doesn't go away. I don't know what to do about it. This is the actual side of this camera, or maybe my specific unit. They just don't disappear completely, that's all.
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Pavel ZhukovReply to malex
I wrote about it because I had the same problem. In this case, offset is the value that the software adds to the pixel signal value, not the calibration offset frame. I solved the problem as follows:
1. The offset value when shooting darks and lights must match and be such that the dark histogram is not clipped on the left.
2. I don't calibrate with biases. The camera has low read noise, plus the bias is already contained in the dark.

As soon as I corrected the two issues above, everything immediately worked out.

Additional notes on calibration for this camera:
- I calibrate with flats, and I calibrate the flats beforehand with dark flats.
- I shoot darks at home after a session using a refrigerator and freezer. I monitor the temperature and move them if necessary. A few days and a dark library for the year is ready, from -10 to 35 degrees.
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