Markarian and Friends

[Annehouw]

This 2 pane mosaic was the first outing of my FrankenOptics scope on a iEQ30 mount and also my first mosaic. There maybe some interesting learnings for others, so I will describe my experiences in making this image a little bit:

-The refractor is a collection of pieces screwed together with tape in two places. The objective cell is a William Optics 80mm f/6.9 FD ApoGrade. This is an upgrade that was sold many years ago by William Optics to convert a semi-APO Megrez 80SD into an APO refractor (Megrez 80FD). The tube is not original, the focuser had variable slack, and the original focal reducer/flattener was OK at the time for tiny sensors, but not for my current APS-C camera (QHY168C). So, I bought a "cheap" focuser (GSO linear) and a not so cheap WO 6AIII reducer/flattener. Long story short, I was not able to completely eliminate tilt and curvature, but enough to my liking (and patience). I taped both the focuser and the variable ring reducer, so I would not inadvertently mess up with the alignment during transportation. There is color fringing in this scope, but it is not that bad (it still is a doublet). So much for the eccentric bit.

-The iOptron iEQ30 that I had bought second hand last year turned out to have a periodic error of 60 arc seconds (peak to peak) and at some points a bit steep. I had 4 clear nights in a row for making this image. The first night I could not guide better than 2.5 arcsecond RMS in PHD2 (elongated stars). My image scale is 2.2 arcseconds, so this is not good enough. I improved on this every night until I got to 1.2 arcsecond RMS the last night. Not stellar, but just enough for this image scale. The trick that did it for me was using the Predictive PEC guiding in PHD2, combined with short (1sec) guide exposures. There was also quite a bit of DEC backlash, but that was manageble. I have found some tuning tips for it's big brother, the iEQ45, so I might give that a try in the summer months.

- I used a ZWO290 camera as my guide scope and once I changed the driver from ZWO native to ASCOM in PHD2, typical snr skyrocketed from 15-20 to almost 200. The image shapes changed from spikes above a noise floor to nicely formed bell shapes with a nice peak. Strange but true.

- I planned the panes in telescopius.com and that worked very good!

- Both panes were pre-processed separately in AstroPixelProcessor. Generating the mosaic was a non-event. I followed the guide of the tooltips and it worked on the first try.

- Because my wrestling with guiding, the stars are not really round, but because it is a mosaic, it does not show that much.

- Post-processed in PixInsight with a final touch in Photoshop CS6

There is a larger version here: https://www.astrobin.com/mgo1hr/ with acquisition details and a mouse over shows a great many galaxies in this image.

 

CS, Anne

 

 

 

Edited May 7, 2020 by Annehouw

[MarkAR]

That's a lot of friends, well done.

[Annehouw]

Thanks, Mark

Forgetting things like Tak, TEC, AP, PE, Strehl ratio, etc, there is a lot to see here. 

E.g:

Galaxies in the Markarian's chain are part of the Virgo supercluster, as is our Milky Way.

From the Arp catalogue, there is:

Arp 120 (Copeland's Eyes), a galaxy merger in progress.

Arp 76 (M90 and IC 3583). This close pair of galaxies are separating fast and M90 is one of the few galaxies that has a negative redshift (i.e. it is coming towards us).

Then there is M89 with surrounding shells and a plume that is ejected

Last but not least there is M87 with the famous jet and even more famous this is where the Event Horizon Telescope last year imaged the accretion disk of a massive black hole.

 

Now look again at the picture as a whole and think of what you are actually seeing. To quote a well known pointy eared scientist: Fascinating! 😉

Edited May 7, 2020 by Annehouw

[Knight of Clear Skies]

Thanks for the write-up. The jet is showing nicely, don't often see it in long exposure images.

[Annehouw]

Thanks, Knight of Clear Skies

I do not want to rain on my own parade, but unfortunately what you are seeing at the 5 o' clock position are two galaxies. The jet should be at the one o' clock position and whitish in color. As you say, it is best imaged with short exposures.  Maybe next season with a bigger scope....

[carastro]

Excellent

Carole 

[Taman]

Beautiful image!

I think you should go into production with the FrankenOptics scope. Perhaps FLO would sell it for you. 😀

[Annehouw]

@Carole: Thank you very much!

@Taman: Thanks for the suggestion. However, my industrial design skills leave much to be desired......😬

Edited May 7, 2020 by Annehouw

[Knight of Clear Skies]

It has good pedigree. After all, the Apollo lander was wrapped in bacofoil.