Show & tell, 1st November

[rwilkinson]

I can talk about (and maybe demonstrate) a couple of things which I've been working on recently:

• A home-made anti-dewing system
• Can I detect a 14th-magnitude comet using a 70mm 'scope?

Any more offers?

[dean_kos]

Yea I can do a bit on using a fisheye lens......pro's and con's

[DRatledge]

I can give an update on the ADC - the mark2 version..........

[CEtherington]

Hiya. I can do a couple of minutes on the exhibition idea. Also I have a mystery gift for the society.....

[rwilkinson]

I can talk about.. a 14th-magnitude comet..

Well, as I explained last night, it was more like 15th magnitude.

Then after I got home from the meeting I could see that the constellation of Auriga had risen above the trees, so I was able to have a go at it from my garden, using my preferred comet-imaging kit (an old StarlightXpress camera on my focal-reduced 8" SCT):

Comet 226P on 1-Nov. 13x 90-sec with MX716 on C8 at f/3.3.

226p_1nov.png (222.92 KiB) Viewed 5631 times

This is a rather better result that I'd managed last week with the 70mm 'scope - so the gain of the longer exposures and larger optical system outweighed the increased light-pollution (and my LPR filter) plus the hazy cloud which came over during my imaging (so I had to omit some of the sequence from my stack - hence the gaps in the star-trails).

[bbones]

That's brilliant, your expertise using IRIS pays off... Much do more myself

[rwilkinson]

I can talk about.. a home-made anti-dewing system

If anyone would like to make one of their own, this is a source of the "Heat-trace" cable:
http://www.ebay.co.uk/itm/12w-m-TRACE-H ... 0986887824
and the power-controllers which I mentioned:
http://www.ebay.co.uk/itm/DC-12V-8A-LED ... 2161210561

And here's a previous discussion with references to Constantan and Nichrome wires:
viewtopic.php?f=6&t=366&p=1344