DeepSky Camp August 2008

[Carole]

Hi Mick,

I didn't really want to bore every-one with all this but since you asked the question

Carole are you still using rechargeable batteries in your ETX ?

At home I use mains, I sometimes use rechargeable batteries at observing evenings, but as I was going to camp with my 12V battery, and as I had tried running the ETX off it when we did a public Moon and planets evening (because I forgot to charge the AA batteries) and it worked OK that evening, I had assumed it would again and did not trouble to re-charge the AA batteries in time for camp.

It failed initially using the 12V and the guys thought it could be because I didn't have a proper connection and was running it from 12v through the invertor and then through the mains lead which was converting it back to 12V again.  So after it failed twice using this method, I switched to the AA batteries which as I said I had charged up 2 or 3 few weeks ago but had not done so immediately prior to DSC and they worked OK until aligning the 2nd star and then I got a Motor Unit failure again. 

I am hoping that it is because the 12V method was unsatisfactory (but why did it work OK for a whole evening once before) and the fact that the AA batteries were also flat.

Only one way to find out and that is to have a session using the mains.

If all is well, then hopefully Mark's adaptation to my old mains lead will hopefully be the answer.
If I still get the same problem on the mains I am in trouble.

Carole

[MarkS]

M16 from Tuesnoad on Friday night.

10 subs of 5min at ISO 800.  That's all I could manage before the clouds rolled in.
Modified Canon EOS 350D on Celestron C11 at F6.3
Image has been stacked, dynamic range scaled then binned to 1/3 size before cropping.

I had no filter in place so this image also contains an infra-red component - I don't know if that's a good thing or a bad thing.

Ambient temperature was 18C.

[Carole]

Nice to see the final image Mark, looks great to me, nice round stars and lots of detail.  Was very difficult to see what you had got on the DSLR LCD screen but as usual you have done a good one.

Carole

[MarkS]

Sundog at Tuesnoad.

7:20pm on Saturday 2 August.  Most of us saw it - just before we sat down to one of Mike's wonderful Chillies.

Nikon D70, 18mm at F13. 
ISO 800 because I'd stupidly left it at a high setting.

[Tony G]

Hi all,

Here is a image of Jupiter with the ol' faithful Toucam, (still need to learn the processing bit )



This also has captured the transit of Europa to the top left, but there seems to be something below to the right of the Red Spot any ideas?
I didn't know whether it was another moon or a shadow of Europa or something else??????????

Tony G

[MarkS]

Contrail casting a shadow on Cirrus(?) clouds at Tuesnoad.


We saw this a few minutes before the sundog on Sat 2 Aug at 17:17 BST.

Nikon D70.  24mm at F16.

[MarkS]

Tony,

That's a great image of Jupiter.  You should be very proud of that one!

Mark

[Daniel]

Wow, some gorgeous images here, Loving Mark's M16 especially, the colour is so much more varied than I've been able to capture so far, when you say the image is binned, what software are you doing this in?

Would love to have seen that sundog, could have ticked that off of my 50 things to see list in Sky at night magazine this month

[MarkS]

Daniel,

Binning done in IRIS - it's the only way to reduce image size because it sums adjacent pixels into a single pixel - thus reducing noise as well.

Mark

[Fay]

Great images, Tony & Mark, glad someone managed to get something of the lovely sky between the cloud passes.

Clouds look good to me, Mark. 

[Rocket Pooch]

Mark & Tony,

Very good, I suppose all the moaning we did about the cloud was not as bad as it could have been eh!

Chris

[RobertM]

Great pictures guys !  The sundog shows up very well, a great photograph.  The Jupiter image is amazing considering how low it is with the GRS showing up really well.  I do think there's more detail in that image John, try processing it a bit more ...

That eagle image is showing a lot of the surrounding nebulosity Mark and it looks to me like it's been very well processed, very smooth and little if any noise.

[Mike]

....I do think there's more detail in that image John.....

Tony

[JohnP]

Robert it's easy to confuse Tony & me..... 

Anyway - Mark - I love the M16 it looks very smooth & great detail (Can you explain your focus technique again please). Only comments I have is that stars look a little bloated but I guess that may be down to IR component...? Considering how low down this is it's a great result - Is there any chance you could post a full sized crop of the centre? The guiding looks like it was spot on which amazes me considering PHD kept loosing the guide star...

Tony - You Jupiter shot is fantastic - I am not sure that the satellite transit is Europa - according to SMP it is Io but I may have timings wrong etc. Anyway I love the image & like Robert says there is probably more that you could get out of it... Well done anyway it's a real decent picture of Jupiter.

Carole - Your Jupiter image is good considering all the equipment issues you were having - well done.

Chris - Your veil image looks like it has tons of detail in especially the Ha raw that you emailed to me. I can't wait to see the final result when you have had a chance to put it all together.

Love all the cloud shots etc. We seemed to be blessed with Sundogs at DSC - I remember taking some images a few camps ago.

John

[MarkS]

John,

Yes,  I think the IR component has caused extra star bloat.  I'll post a full-size crop of the centre tonight.

As for guiding, M16 is my very first image where I have guided using a newly built lead from the parallel port straight into the ST-4 port of the mount.  The guiding is now far more positive than when I used the lead that went from the serial port to the handset. 

PhD beeps a warning when the signal to noise ratio of the guide star drops below 3 but luckily this only happened for brief intervals on M16.

My DSLR focusing technique is as follows:
1) If you don't have a scale on your focusing knob then create a makeshift one - my makeshift one has 9 marked positions. 
2) Roughly focus the camera by eye through the viewfinder on a brightish star
3) Now slew to some faintish stars
4) Move the focus knob back 4 gradations on the dial.
5) Take an exposure of 36 seconds whilst continuosly slowly slewing the scope and every 4 seconds move the focus knob to the next position.
6) Examine the star trails on the image (but not the saturated ones).  Those star trails will allow you to determine which position of the focus knob gives the sharpest results.
7) Set the focus knob to this new position
Repeat steps 4-7 until satisfied!

http://homepage.ntlworld.com/the_shelleys/photos/SlewFocusing.jpg

Why do I have to do this?
1) Because the USB 1.1 (or 1.0?)  port on my laptop is extremely slow to download images direct from the camera.
2) It also means that no laptop is needed at all (except for guiding).

I do the same thing for widefield work with a lens because the infinity setting on some lenses is not always completely accurate.

Mark