straight through viewing

Hi, I have picked up a Pentax refractor, only 75 mm but very, very nice images. Unfortunately it is not intended for using a diagonal; it will not come to focus with one. How does one accomplish straight-through viewing for objects above, say, 30 degree elevation?

Robert Howe

Attached Image:

Robert
Have you tried a 1.25" diagonal?
Buck

Not really an answer to your question, but here's a review where this issue was at least noted:
http://cloudynights.com/item.php?item_id=1164&pr=2x6x13

In any event...looks like a great scope!!

btw - the review mentions that you can put a barlow in 1st, then the diagonal, then the EP and that works. If that's the case you could always get a 1.5x barlow or a 1.25x barlow so you have minimum mag and get the focus length you need. I think Siebert will make you up a 1.25x barlow.

Hi Robert,

I noticed on OPT web site that Pentax have a 1.25 inch diagonal, which is claimed to work in most Pentax scopes.
Worth at look.

Bill

A couple of years ago I visited a Yahoo group dedicated to stright-through viewing. Most of the folks were European and quite knowledgeable and commited. Maybe you can start a search for that group.
I don't do Yahoo groups so I don't know how to find them.

I've seen numerous articles on Japanese star gazing and they are very comfortable at straight thru viewing i.e. sitting or doing the squat. Bit of an Asianphile here...wouldn't be the first thing culturally Japanese are comfortable at simply doing the squat. 8O :S

Robert,
Fellow refractor ardent Rob Wiederich has some kind of raising and lowering pier for his 6" f/15. I'm sure he'd tell you about it if you got his attention or wrote him off-forum. I have seen survey instruments that cranked up and down with a rack and pinion arrangement that would be nice for your scope. Of course you still have to have a good neck for near-zenith viewing, but it would get the strain off your back and legs.

It seems I have read that the Japanese straight-through observers think looking up reduces the amount of "floaters" seen on bright planets at small exit pupil. I've never tried it, but I have noticed that I can control my floaters better in some positions than others, so there might be something to it.

Ron

This is an off the cuff suggestion -- perhaps a parallelogram mount?

I wouldn't think that the weight of a 75mm scope would be prohibitive; perhaps there are other problems with such a set up that haven't come immediately to mind. ( I have never used a p-mount.)

Steve C.

Robert

I'm pretty sure you tried this already, but just to make sure: have you tried a quality prism diagonal. I had a refractor that did not have enough forward travel for my Televue 1-1/4" mirror diagonal, but it worked fine with a Meade or a Takahashi 1-1/4" 90 degree prism diagonal?

As far as straight thru viewing. I'd recommend getting an alt az mount with a taller good quality tripod and a short stool (adjustable would be best) to get as comfortable as possible. Do most viewing from 30 to 60 degrees above the horizon (above the thickest atmosphere and below a severe neck strain).

I've never personally looked through a Pentax, but all reports are that it's top quality, so enjoy.

Steven Jindra