Imaging Refractor please help me choose one

[Kai]

Please help me make a choice between a Pentax 75SHDF or a Takahashi FS60CB.

I am planning to use them for widerfield imaging along with a Atik 314L.

As far as i can make out its a close call between the two , with slight differences between the two.

Which one should i get and why

Cheers

Steve

[Milamber]

Pentax... no question, best flatfield you'll ever see for the aperture/money. And *so* sexy too

Arthur

[Kai]

And *so* sexy too

:laughing3: :laughing3: :laughing3: I suppose i should of asked about Drool factor as well

[GazOC]

Its a very important consideration with refractors.

[Milamber]

Yup - 'cos you sure as hell can't shave with them ...

[Kai]

The only downside to the Pentax is as far as i can see a Rack and Pinion focusser as opposed to a Crayford.Does anybody have first hand knowledge about how it copes with CCD's attached ??

[Milamber]

It's a damned good focuser Steve, it was designed for LF cameras and I have not heard of anyone complaining about slippage with it. I can't remember now but is it a 2.7" native with a 2" adapter?

Arthur

[ngc2403]

hey,

might i point out that the Pentax scopes are NOT apo's or even semi apos they are achro scopes unlike the Tak which is an excellent doublet apo and the perfect travel scope.

with the smaller chip in the Atik than say an DSLR the flat field in the tak should be more than enough to use with the CCD and be fine for DLSR's as well i think though there are a few one this site who use the tak with DSLR so they could tell you better than me.

i don't know prices but i would get the tak if i could either

ally

[Milamber]

No - they were not apo - but with a huge flat field any aberation is usually way outside the usable area.

[Kai]

hey,

might i point out that the Pentax scopes are NOT apo's or even semi apos they are achro scopes unlike the Tak which is an excellent doublet apo and the perfect travel scope.

ally

Sorry to disagree Ally but where did you get that info ???

According to both FLO and Ian King the Pentax IS a Apo

http://www.firstlightoptics.com/proddetail.php?prod=Pentax75SDHF

http://www.iankingimaging.com/show_products.php?category=103&offset=10&offset=0

:scratch: :scratch: :scratch:

[GazOC]

What is it? A Petzval?

[ngc2403]

they say APO but it's not perhaps it's semi apo looking at some of the picture online but the older Pentax were not APO's ever i will try finding a picture

[Kai]

they say APO but it's not perhaps it's semi apo looking at some of the picture online but the older Pentax were not APO's ever i will try finding a picture

I'm sure Ian and Steve would not try and mislead anybody , maybe the older Pentax's were not Apo but i am talking about the 75 SHDF which as far as i can make out is.

What exactly makes you so sure ???

[ngc2403]

Hey just found this on cloudy nights,

an image from the Pentax with a full frame CCD, not sure how it was taken but i don't think he adjusted between shots for focus,

(click to enlarge)

check out the stars in the corners?

colour and not point like????

ally

[mik]

Tak for me it is so cute

Mick

[Kai]

Do you have a link Ally ??

[mik]

Take a look here Steve

http://telescope-service.com/pentax/pentax-images/pentax-75.html

[Whippy]

Well, OPT (who represent Pentax's astro kit in the US) have it down as an APO: http://www.optcorp.com/product.aspx?pid=8732 . APO or not, it's the bizz .

Tony..

[themos]

why not Borg?

[Kai]

why not Borg?

They scare me in Star Trek

[ngc2403]

i know that they all get called apo's but they don't put colour correction at the top of the list for telescopes properties (hence not full Apo IMO), they concestrate on the flat field.

some people like that others don't, i don't care to much for them but i understand the appeal.

plus to fix the CA with a mono CCD imaging setup them you can adjust the focus between filters.

link for the cloudynights talk about it

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2660554/Main/2659940

ally

[Kai]

As Ben is a member on SGL i hope he might catch this thread and give me his opinion.

To be fair as i said i plan on using a Atik 314L so the chip isnt that huge in comparison to DLSR's so i do not think it will be a major problem.

Thanks all

[Whippy]

Alternatively, you could always go for that Tak Epsilon 130 on AB&S, widefield and fast .

Tony..

[Kai]

I know Tony , i did see that this afternoon

[Whippy]

Nowhere near as sexy though is it.... a Yellow reflector....

Just out of curisoity Steve, have you considered the WO ZS66? I've been using mine and it appears to do the job pretty well. I figure you won't need the huge flat field of the Pentax as the chip on the Atik is tiny in comparison.

Tony..