Moon Shot

Do you fill in for Jodrell Bank on their days off

would you be able to do moon shoots with a mirror telescope

James

Yep a reflector should be able to get decent moon shots. I believe reflectors are better for deep space and refractors are better for solar system / planetary stuff....or so I've been told.

Just looking for Pentax DSLR Moon & astro shots on the forum for reference when testing my K5 and came across yours Ted ...fantastic result there, quality result!
Prime focus telescope shots are certainly the way to go and refractors seldom disappoint. A flat field low power barlow lens (1.4X -1.6x)and screw in OR slot in extension tubes can increase the image size and retain definition to the edge of the frame...much like an enlarger lens onto paper but in the case the sensor OR film.
Eyepiece projection is good for the planets where higher power is required but as you found hard to get everything in focus across the entire field.

I would love to see more astro related images done with Pentax DSLR's as mostly Canikon dominated.

Mike

I'm considering tinkering with an astro-scope for bird photography sometime this year.
Over on birdforum.net there is a dedicated forum for photography using astro telescopes and, having seen some of the results on a couple of member galleries, the quality is incredible. I'd go so far to say that some of the results I have seen are right up there with some of the financially out of reach primes on the market. Ok, there's a bit of experimenting to do and manual focus only of course but still, it's worth looking at when a good ED 80mm scope can be had for around the £400 - £500 mark.
Another interesting concept is the new Lens / Spotting Scope from Kowa - also mentioned on the same site as above in the spotting scopes section.

At least there are some long glass options available out there, even if they are all manual only.

At the risk of hijacking Ted's thread there are some prime astronomical telescopes out there with optics to outperform the best dedicated camera telephoto lenses ...less glass but finest quality and in some cases calcium fluorite crystal.

As you say the drawback is lack of autofocus though motor focusers are currently in use all that would be needed is a fast focuser with a way of interfacing with a DSLR autufocus system, perhaps just a connector lead.

The technology is there we just need some clever people to marry everything together.

Mike

Having just come across this thread, I can add to Father Teds comments (of over a year ago) on linking cameras & telescopes. There are apparently three different techniques that can be used:

Prime focus with no lens/eyepiece (called negative projection it a barlow is added)

Postive projection with eyepiece but no camera lens

A-focal using both an eyepiece & a camera lens (often a compact camera or even web cam)

I can't help wondering if it's not possible to use a camera lens with no eyepiece but I've never seen this permutation mentioned.

With my Newtonian it seems I have to get the camera into the telescope tube to achieve infinity with prime focus, & I've never managed to nail the focus when I've tried positive projection either - here it is slightly beyond the focus range but with the eyepiece only partially inserted or with an extension it should be possible to achieve focus eventually.

All I really need now is several years of comfortably warm, clear, dark nights (on which the kids have gone to bed...) to practice technique. Then I should be able to get close to Teds results. His scope is better for this but for the moon that shouldn't be an issue.

In the meantime I'll keep reading tips on technique.

Newtonians are renowned for lack of back focus but here are some options others have used to solve the problem. These modifications are difficult and not advised.


1. Custom fit a low profile focuser rather than the standard rack & pinion focuser usually fitted, this 'might' give enough adjustment to reach focus.

2. Move the primary mirror 'up' the optical tube to compensate focus issue.

3. Have a newtonian telescope custom made to reach focus with your imaging device/setup.

4. Sell it and buy a refractor or cassegrain reflector, both designs usually have more back focus than a Newtonian.

Newtonians have traditionally been used for visual but with imaging comes focus issues. When designed with imaging in mind Newtonians are relatively inexpensive and produce great results.

Mike

This may be a bit a a 'stupid' question but with the K-5 could you use the 'Catch in Focus Mode'?
I am tinkering with the idea of using my 8" reflector. I got the voucher to get the connector for the Reflector/Pentax K from a local shop next week.
Just wondering if for some (if they got the K-5) this feature would be a possible workaround the focussing issue?

Well I know a bit about astrophotography but DSLR's ...I'm still on the learning curve there and doing so with the K5.

The K5 instructions do say a manual focus lens which would probably include a telescope by way of a PK T-adapter but to be honest not sure if 'catch in focus' mode will work, if it does the Moon would be a good test but might struggle with stars or darker subjects. This mode might only be useful to find focus manually using the telescope rack & pinion focuser then it would have to be hands-off using a cable release a few moments after the any vibration has died down after manual focusing.

I was out doing a quick test of the K5 on the Moon the other night using a Pentax 67 800mm EDIF lens, will post an image soon under a new thread with further information rather than hijack Ted's thread here.

Mike

I am sure that Ted would not mind to discuss a couple of technical details here as we sadly do not have a particular forum for this kind of photography, or so I hope.
(John, maybe an idea to put up a forum of using Telescopes and Spotting Scopes? I would be all for it and it seems that's there are quite a few here with this interest. It also would mean that no-one has to hijack someone's thread and it would be easier to find threads with this particular technique or interest combined with a Pentax Camera?)
Anyway, could you not use the 'mirror up' settings?
I may start a poll for including a new forum that particular deals with Telescopes and Spotting Scopes as this seems to be of interest for many here. See what comes out of it.

Nice picture
The detail there is.
lacks three-dimensionality, though maybe it's my monitor

Mirror lock up is certainly the way to go as vibration is the enemy of long focal lenth imaging. Live view is currently used to advantage for manual focusing in this type of photography too. Beyond the 800mm setting, the maximum in the K5 menu the SR may not be enough to cancel out vibration at extreme focal lengths and mirror lock up with shutter time delay would probably be better.

Considering the growing popularity of using telescopes & spotting scopes with DSLR's for astronomical & long focal length wildlife photography perhaps there is an opening for another category, there is after all a category for everyones excellent 'Macro' images ...'Specialist' seems to be the only other option to post in at the moment plus the other extreme in focal lengths would create a nice balance in the images posted so please go ahead, a poll would be interesting.

We could still use Specialist or Landscape for the wide field related subjects.

Would suggest category... Telescope/Spotting Scope/Telephoto

Mike

Very nice shots crisp and clear well done.
Ian

Would be great if you could go here and repeat this one as I fully agree. Maybe if we get enough votes we would get a category like this.
Anyone else that would be interested use the link and vote there to see how many would like to see a special category like this.