Search found 396 matches

by DRatledge
Sat May 23, 2020 7:47 pm
Forum: Astrophotography
Topic: Is it real?
Replies: 0
Views: 840

Is it real?

When running through the processing of the Cocoon Galaxy (NGC4490) recently I noticed a faint blob at its left (east) end – I've indicated it with red lines. Is this really there or is it as a result of next door’s outside light? With very faint objects it is often very difficult to decide what is f...
by DRatledge
Fri Apr 24, 2020 3:10 pm
Forum: Astrophotography
Topic: Filter or No Filter?
Replies: 0
Views: 3451

Filter or No Filter?

With the widespread adoption of Led street lighting I have been using no filters for my luminance (black and white) images this winter. Has it worked? To check I recently imaged M51 without a filter to find out. I had imaged it in 2009 and 2011 with a light pollution filter so I could do a direct co...
by DRatledge
Sat Apr 18, 2020 5:15 pm
Forum: General - Discussion
Topic: Planetary Exercise
Replies: 3
Views: 1870

Re: Planetary Exercise

eris-plan.jpg
eris-plan.jpg (174 KiB) Viewed 1692 times
If you haven't solved it then I hope this drawing should explain how to do it. Because of the crude assumptions the answer is 15% too big but does show that Eris really is Extremely Remote In Space.

Peter - the images I take are what I am interested in and have read about.
by DRatledge
Fri Apr 17, 2020 7:32 pm
Forum: Astrophotography
Topic: Imaging Session - what goes on
Replies: 0
Views: 3629

Imaging Session - what goes on

In these strange times I thought I would explain how one of my imaging sessions works. Attached is a screen dump of my observatory computer viewed from my indoor computer! I have 3 programs running in the observatory, the first that controls the cameras; another that maps the sky showing where the t...
by DRatledge
Sun Apr 05, 2020 9:51 am
Forum: General - Discussion
Topic: Planetary Exercise
Replies: 3
Views: 1870

Re: Planetary Exercise

Peter, I did give some big clues as how to calculate it and I cannot really spell it out without spoiling it for others. Remember I said assume Eris hasn't moved - you can also assume the background stars haven't moved so all that has moved is the Earth. If you draw a plan of that then it should bec...
by DRatledge
Tue Mar 31, 2020 11:57 am
Forum: General - Discussion
Topic: Planetary Exercise
Replies: 3
Views: 1870

Planetary Exercise

How far away is the minor planet ERIS? This was an exercise I set recently for Bolton School Astronomy group. Its distance can be estimated with simple maths using the image below. This is a composite of two images taken 4 days apart and ERIS is shown in its two positions. The answer is in Astronomi...
by DRatledge
Thu Mar 26, 2020 1:50 pm
Forum: Astrophotography
Topic: Comet Atlas - first try
Replies: 0
Views: 3766

Comet Atlas - first try

Predicted to brighten considerably next month but I thought I had better have a try last night (25 March). It has a good tail though already. Below is a very rough stack of 26 x 4 minutes on the Comet so the stars all but disappear. Need to clean this up, get rid of the noise, add it to the star fie...
by DRatledge
Sun Mar 22, 2020 9:28 pm
Forum: Astrophotography
Topic: Bulls Eye
Replies: 2
Views: 1931

Re: Bulls Eye

A second clear night - wow. But another Bulls Eye!
PS the object is too faint to register in this single image - I hope it appears when I add them all together.
by DRatledge
Fri Mar 20, 2020 9:03 pm
Forum: Astrophotography
Topic: Bulls Eye
Replies: 2
Views: 1931

Bulls Eye

I thought aeroplanes were no longer flying? First decent clear night for weeks and first shot I get a bulls eye!
by DRatledge
Sat Oct 12, 2019 7:20 pm
Forum: Astrophotography
Topic: CCD Astronomy – the End of an Era?
Replies: 0
Views: 8413

CCD Astronomy – the End of an Era?

It looks like we are coming to the end of CCD astronomy – well at least for us amateurs. Sony have signalled they have stopped developing CCD imaging chips and now On Semi (formerly Kodak) have just announced they are terminating production. This includes the popular KAF range of sensors found in ne...