Astrophotography with an inexpensive 80mm f/5 refractor

Eight years ago I purchased a Meade 80mm f/5 refractor brand new for $90.  The specific retail package was advertised as the Meade "Adventure Scope".  I discarded all the cheap accessories and upgraded the optical tube with a GSO Crayford focuser and some tube rings and dovetails.  This scope is now going to be loaned to the Lookout Mountain Observatory Association in Del Norte for the purpose of developing a way to electronically display images in near realtime at public events.  Before it leaves home, however, I wanted to take some pictures to establish a baseline expectation for what might be achieved.

Here is a picture of the scope from the retail packaging:

 

And here is what the new configuration looks like, with an ASIAIR mini control module and an ASI294MC-PRO cooled astro camera:

 The sky was clear enough on Thursday night (02 July) to take some photos using this scope with an Olympus E-M5iii camera, riding on a ZWO AM3 mount.  The moon was rising, though still hidden behind the ridgeline of Snowshoe Mountain.  Because of the rising moon, sky brightness was only 20.5 mpsas.

This scope is an achromatic doublet, which comes with two flaws that affect astrophotography.  The first is field curvature, and the second is chromatic aberration in the form of purple fringing.  To mitigate these problems, these images were obtained with a field flattener and a UV/IR cut filter. 

All of the following images are single exposures of between 30 to 60 sec. 

M8, the "Lagoon Nebula"

 Messier 8 (M8) is in the constellation Sagittarius in the heart of the Milky Way. The cluster in the lower left of this image is the globular cluster NGC 6544, about twice as far away (9800 ly).

Star cluster M21 (near center) and M20, the "Trifid Nebula" in Sagittarius.

 

Open cluster M23 in Sagittarius

Open cluster M25 in Sagittarius

Globular cluster M22 in Sagittarius

Open clusters NGC 6716 and Collinder 394 in Sagittarius

The scope was also used to view a few of the nearest stars.  

Barnard's Star in Ophiuchus

 Barnard's Star, at 5.96 ly, is the second closest star system after the Alpha Centauri system.  It is a magnitude-9.5 red dwarf star.

Ross 154 in Sagittarius

 Ross 154, at 9.71 ly, is the seventh closest star system.  It is a magnitude-10.5 red dwarf star in Sagittarius.

 

61 Cygni

The double star 61 Cygni (in Cygnus) is the 14th closest system, at 11.4 ly.  The two slightly uneven components are each about 2/3 the size of our Sun.