New image scale Joop 19th May

[asimov (John)]

Seeing conditions were pretty ordinary when I took these, but the image scale has potential! Time for some seeing above 4/10.....PLEASE?????

F10 C9.25 SCT 2X barlow 75mm extension tube & diagonal {F30something} 150 frames each.

[Lester]

Hi Mate,

I think the large image scale has real potential. The further the image can be spread over the sensor must help to minimise image break down. I guess the ideal if the mount tracked okay would be to fill the sensor with the image. Ofcourse then mount stability comes into it also.

I have got 3 extention tubes might give it a try tonight on the 14".

Asi if it looks clear tonight you can come out, I realise you don't want to go late.

[davidpretorius]

another 9 to go for damian peach scale.

cmon mate, bugga the seeing & results, lets see f50!!!!! I want to see the toucam scraping the ground or if using the diagonal, i want you sitting on the roof with the lappie!!!

at least you can see the planet, i have forgotten it's name, its been that long!

[[1ponders] (Paul)]

Asi, if you want to get huge image scale then there are alternatives to using a barlow and extension tubes. Using Positive Eyepiece Projection you can get any f ratio you want by varying the fl of the eyepiece the the distance the ccd chip is from the eyepiece. I put a calculator I put together up on the site the other day. It is based on using the Meade vari-extender. If you are interested there is a zip file containing the excel spread sheet here

[asimov (John)]

Hey, just went to the dump & came back home with 15 vacuum cleaners & pipes/handles/watever-yacall'em! to make extension tubes. Also rang a contractor with a backhoe to dig me a 30 ft deep hole south-side of the mount! Too cold to sit on the roof dave! > <

In all seriousness, this is enough scale, the eq5 can't take no more!

Thanks for the info Paul, Lester, you have a tele extender don't you??

[asimov (John)]

Oh & thanks Lester, 7 ok?

Sorry to hear you ain't getting any Davo, your turns coming again soon I've had a word in the weather gods ear(s)

[davidpretorius]

Originally Posted by asimov

In all seriousness, this is enough scale, the eq5 can't take no more!

what is this? asi admitting there is a limit.................000, we have an emergency, please despatch immediate assistance to cummin in SA.....

easily fixed i reckon, build a titan mount out of car parts!!!

[asimov (John)]

I have a better idea...just strap the C9.25 to Lesters 14" on his Goliath mount! It would take it no sweat....Are you game Lester?? 'cos I am!

[[1ponders] (Paul)]

Asi I'm looking forward to the day you have to make a mosaic of Jupiter to get a complete image

[asimov (John)]

LMAO Paul! Now that would be something to see! ....

[davidpretorius]

paul, don't egg him on!!

he's dangerous enough already!

[Lester]

Hi Freind,

Yep thats a roger. The C9.25 wouldn't be much heavier than the C8. We will have to modify the cradle I use to use for the C8.

I have got 3 teleextenders.

Only hassle mounting the 9.25 on my mount is the inconvenience for you; if its not an issue we will do it.

I have got some more fencing to do this afternoon, you could come out at 4 and Bob's your uncle.

[[1ponders] (Paul)]

If you have a good Plossl or orthoscopic in the 15-20 mm range, give the Tele-extender a go. Assuming of course you have the adapter to go from the end of the TE to the ToUcam. (See here below the standard adapter .

[asimov (John)]

Cheers again Paul..Your a weath of information! thanks!

See you at 4 Lester!

[[1ponders] (Paul)]

Here, here's an example.

Both images taken with the 8" meade SCT
Image 1 using a 2X barlow after the diagonal.
Image 2 using a 20mm plossl in the Tele-extender, unextended and screwed straight onto a T thread on the back of the OTA (no diagonal).

I did have some images from a fully extended TE that took up half the chip but I deleted them 'cos they were Complete Rubbish After Processing due to terrible seeing The second one here isn't much better.

[asimov (John)]

Hi again Paul.

Good idea to have the different image scales side by side.

Heres the difference in size with my setup. First image: 2x barlow with my extension tube (640x480 pixels) 2nd image: 2x barlow with my extension tube & diagonal added (640x480 pixels)

All with the F10 SCT of course. No cropping on images.

[[1ponders] (Paul)]

So what's your configuration of barlow/extension/diagonal/ToUcam?

B/E/D/T
or
D/B/E/T
or
B/D/E/T
or
E/B/D/T
or
E/D/B/T
???

[asimov (John)]

B/E/D/T Paul. Having anything primary mirror side of the barlow does nothing...apart from having to travel a long way to get focus.