Light path lengths & Problems with focus

[Mac]

I did have a quick play with maxim and auto guiding with the H9, but as that was only a quick play, i didn't
realy achieve anything, but as i've now found my toucam, im going to have a play with it set up on the nikon lens,
F300m + 2X tele convertor + toucam,

should be around the same focal length as the main scope and the F3.3.

I i'll have to have a go and se what errors i get.
I've also been looking at using software to train the scope for the PEC, which i still need to do,

So if i get the software to do the PEC, i can leave it auto training for about an hour, which should give it plenty to chew on.

I;ve also started to balance the scope, which is giving me weird headaches, but thats for another thread.

Mac.

[JohnP]

Hi Mac,

Not sure but I think you need to be careful when implementing PEC training & autoguiding software together as they can 'fight' against each other & you can endup with worse guiding... I might of course be talking a load of ****ocks......

Any chance you can email me a 5min dark from your H9 - If you could email me the fits file that would be great...

Thks,  John

[Mike]

Not sure but I think you need to be careful when implementing PEC training & autoguiding software together as they can 'fight' against each other & you can endup with worse guiding... I might of course be talking a load of ****ocks......

No that is perfectly correct. Guiding will try to correct movements made by the PEC as they don't talk to each other. When guiding turn PEC off. PEC is to allow longer exposures unguided only.

[JohnP]

Cheers Mike...

[Mac]

I'll make sure then that the PEC is off, as of now.
Thinking about it, I havent actually switched it on.

I dont know how long it takes to cool down, but i'll get it up and running and post a 5 min dark later, any advances on 5 mins.

Acording to the blurb, it will take over 100Hr's to saturate the chip. I'll think i'll take their word for that one.

I'll give you the room temp as well so you can get an idea of the chip temp.

Mac.

[JohnP]

Thks Mac - I'm just interested in seeing how many hot pixels there are.... John

[RobertM]

Mac, could you do a 10min dark so I can compare it with mine.

Cheers
Robert

[Fay]

Wow, Mac, how exciting.

I wish I could help but got lost a few posts back, regarding your equipment setup.
I found there was a lot of testing with additional aids, to all different positions until the correct place was found for everything & it changes depending on what scope etc you are using. I have to think a bit everytime I use a different camera , scope filter wheel or no filter wheel etc etc etc, what to unscrew, add, change around!!!!!! Then the guiding goes wrong!!!!! 

[MarkS]

Mac,

I agree you should use option 1:  scope - Focuser - F3.3 - Filter wheel - H9.

You had the following worry:
"I was just wondering if by placing the F3.3 after the focuser would it cause any problems? as the reducer itself is now moving? so although the light would be able to be brought to focus, would the image size shift?"

I've done a bit of diagrams and maths.  Yes, it is true that when you change the filter, you may have to refocus (glass thickness etc.) but I am confident enough to bet you a pint of beer that the image size remains identical.

Mark

[Mac]

As requested, here are the three dark files

1) 5Mins Fit, after the ccd had been cooling for 20 mins,   http://www.macrhon.co.uk/website/oasphotos/darks/5min.fit
2) another 5 min fit, taken straight after the first one       http://www.macrhon.co.uk/website/oasphotos/darks/5min2.fit
3) 10 Min Fit, again taken straight after the second one.   http://www.macrhon.co.uk/website/oasphotos/darks/10min.fit

havent checked them myself yet,

Just fixinging someones pc and building the nursery. 

Mac.

[Mac]

dont forget to right click and save as, otherwise they will open as text files,

[RobertM]

Your 10 minute dark doesn't look right, I reckon you must have some light leakage or something.

[Rocket Pooch]

There's only 100adu difference in that image, if light got in it would be higher than that.

Mac can you take 32 bias frames and average them and post it up here, I want to see if its readout noise.

[Mac]

Your 10 minute dark doesn't look right, I reckon you must have some light leakage or something

Well i didnt move the ccd at all, it was just sitting there on the box, with the 1 1/4 adapter on, and the rubber cap over the end,

The room temp was probably around 18~20 deg,

and it was taken straight after the two 5 min subs, so if anything they would have the same light leakage.

I'll do another 10 tomorrow, and i'll take the 32 bias subs,

Can i average them in maxim or do i have to use, DSS?

Mac.

[JohnP]

Yep - I checked it in Aip4Win as well & the 5mins show a slighly brighter patch through the middle but like Chris says there is only about 100ADU between the brighter & darker bits.... don't think that would be an issue at all.

The number of hot pixels is very low & there are only one or two saturated (65,000ADU) pixels...

Looks very good to me...

John