Banner3

Rosliston Astronomy Group

Astrophotography

Click here to return to RAG home page

If you can’t see flash navigation box below, text links are at bottom of page

DSOs from the West Country

Roger Samwroth

8/10/2015

 

It is not spectacularly dark here, but darker here than in the Midlands.

Last night was clear but a bit hazy. Good enough to have a go with the 80mm & PD though.

Not much time available, so I just imaged 3 old favourites, and the results are attached. I liked M33 in particular as because of its size is always awkward with the PD. The main problem with the PD and M33 is M33's size, hence having to use a focal reducer on a scope that already has a focal length of only 400mm.

Processing M33 wasn't that difficult, although it is probably like riding a bike - easy when you can do it! The bulk of it uses "curves" to stretch the contrast as in the document on M51 I did. The "gamma" function in Registax is a simpler version if GIMP's curves.

M33 has an angular extent of 70X42 min or so. A FL of 500mm gives a diagonal FOV of 42min with the PD, so it is pushing it a bit to get most of it in. A X0.5 reducer will give you a FOV of 84min, which is much better. More importantly it will also give you 2 stops speed improvement to f/3.1-ish which is quite fast. My 80mm is f/5, so I get f/2.5 with the reducer.

Home tomorrow!

Roger

M31_Samworth_081015
M33_Samworth_081015
M45_Samworth_081015
[Photos/Drawings] [Techniques & Tips] [Pluto Time] [Photographs, drawiings and video by members of RAG after April 2014] [Andy Mac] [Andrew Thornett] [Chris Howe] [Damian] [Dave Jones] [Ed Mann] [Geoff Dryland] [Julian Palmer] [Kenneth Crichton] [Lewis Brailsford] [Nick Cox] [Paul Bertenshaw] [Peter Hill] [Rachel & David Donaldson] [Roger Samworth]