NGC 3079 Spiral Galaxy and friends

[menardre]

I was finally able to get out last night and do some imaging. The Moon rose around 10PM so I picked NGC 3079 since it is located in Ursa Major which is a long distance from the Moon.

Based on my previous tests of binning, I decided to use 2x2 binning with ZWO ASI2600 OSC attached to 11 inch SCT. I also used Falcon Rotator vice manual rotator since it is more accurate and easier to use. The image train included a focal reducer, T-Adapter (I need to 48mm version for this setup), Falcon rotator, and 48mm-42mm converter. This resulted in proper backfocus distance.

I set the ZWO ASI2600 for -10C, gain 100 and 2x2 binning. That allowed me to use shorter exposures (1 minute). I took 280 images of 1 minute and 50 flats 0.15 seconds (also binned 2x2). The last images were not as good since NGC 3079 was lower in Western sky. I used an updated version of SGP (ver 4.1.0.778) to manage all hardware. NGC 3079 was already past the meridian when I started so no meridian flip required.

I processed with PixInsight. During image processing I found NGC 3079 has company including NGC 3073, MCG+09-17-009 galaxy and the twin quasars Q0957+561A and B. NGC 3079 is a barred spiral galaxy about 50 million light years away. It has a prominent bubble in its center. NGC 3073 is a dwarf lenticular galaxy about 65 million light years away. It is part of the NGC 3079 galaxy group. There is also a quasar Q0957+561A and B that appear as dim stars. It is actually a single quasar that appears as two images due to gravitational lensing. The lensing actually causes a time lag of about 417 days between the two images. The quasar is 8.7 billion light years away.

Based on the results I plan on using 2x2 binning for all my imaging with the 11 inch. The result is shorter required exposure times, smaller file sizes, and shorter processing time. I do not see any impact to the clarity of the image.

Roger

NGC 3079_Spiral Galaxy.jpg (1.35 MiB) Viewed 598 times

NGC 3079_Spiral Galaxy.jpg (1.35 MiB) Viewed 598 times

[NGC7000]

Amazing that you caught those quasars.

The images all appear to be the same ( but for the descriptors in the last image), though I thought the last two contained more stars. I think I was just getting played by my own eyes.

Again, another nice grouping of some not so commonly seen galaxies. Beautiful image!

So you found the 2x2 binning gathered more data in a shorter period of time- did you try 2 minute exposures?

Tom

[menardre]

Tom

All 3 images are the same except one has annotation.

I did not try different exposures for this object. My process is to take a sample exposure and then decide if I need to adjust the exposure time. On this image I started with 1 minute exposure and found that I could easily see the galaxy so I did not increase exposure time. I knew that the almost full Moon would be rising so I tried to keep exposures as short as possible.

Unlike CCD cameras, CMOS cameras binning do not increase signal, but read noise is decreased by about a factor of 2, so S/N is increased. Even with 2x2 binning imaging with my 11 inch SCT is still oversampling (about .8 arc sec/pixel). Due to atmospheric conditions you cannot resolve to less than about 1 or 2 arc sec/pixel. The file size drops from about 50Meg/image to about 13Meg/image. This also impacts download time. I found that processing time also decreased substantially since you are dealing with much smaller files for lights, darks, biases, and flats.

When I do wider field imaging with my refractor, I will go back to 1x1 binning since with that setup the image scale would be between 1-2 arc sec/pixel.

I did not realize that I caught the quasars until I "googled' NGC 3079 and could identify the other galaxies and the quasar.

Roger

[Pete]

Don't you love those deep redshift quasars? You're seeing 2/3 of the way to the beginning of time!

Also, it's most interesting to see that we're both drifting toward similar optical train and imaging setups on the SCTs. With binning, the LP filter and ....

lower shutter.jpg (173.16 KiB) Viewed 587 times

the lower shutter addition to block neighborhood lighting my S/N is much improved, allowing far more aggressive processing.

I envy you your much darker sky and your pinpoint stars.

[NGC7000]

Unlike CCD cameras, CMOS cameras binning do not increase signal, but read noise is decreased by about a factor of 2, so S/N is increased.

Thanks, Roger. I didn't know that.


Pete!- I like that image of your scope. That could be a cover shot for Architectural Digest.