Peter Drew

Hello dcobb, welcome to SGL. I say go for the 10", it will give much better DSO performance than any 8" visually. Unless you are particularly picky, coma visually is no big deal, for imaging it would be an issue but easily corrected with add- ons. You would always wonder "what if" if you went for the 8". 🙂

I've had at least a dozen PST's. Never had a lemon but the best ones were as good as some 60mm Lunt's that I have used. 🙂

3" of snow at the Astronomy Centre so no access unless you have AWD. Have had to give the car door lock the "kiss of life" each morning before I can even start to wrestle with the door. 🙂

To paraphrase an old saying, "There are old PST's and gold PST's but no old gold PST's" 🙂

Technically there are 3 filters in a PST, the etalon followed by the ITF and finally the blocking filter. All 3 are essential to its safe and correct performance. 🙂

I think my first course of action would be to add some gussets to the base plate to pier position. Difficult to tell from a photo but the base plate looks rather thin relative to the dimensions of the pier. 🙂

I have a couple of vintage full aperture glass filters for 8" SCT's. They give an excellent performance but cost over £200 each back in the 1970's. 🙂

The "secret" of Baader type film is it's thinness. It's so thin that it has no optical effect even when in a relaxed undulating state. Pulling the material taut in order to make it look flat stretches the material and causes distortions. 🙂

The triplet design may well provide an improvement over doublet binoculars, even ED ones but made to perform at 20x there is no incentive for the manufacturer to specify optics for much higher magnifications. I would expect that the emphasis would have been for colour correction and field flatness for which a triplet should be superior. 🙂

Could just about see where the Sun was today through the thick fog! ☹️

An interesting project with the potential for two 80mm triplet refractors. However, as they say, there's no free lunch. I would be surprised if, even a triplet, from a binocular designed to cope with 20x magnification, would have aspirations much beyond that. Another caveat could be that the correction of the objectives may be balanced to the optics further downstream which might make their inclusion essential for well corrected performance. I would certainly try and devise the alternative arrangement to enable the binocular to be rebuilt back to the original should the experiment prove disappointing. 🙂

Don't forget that Galileo would have been green with envy if you showed him your scope. Using any modern scope is good practice for later upgrades. Hope your wife recovers soon. 🙂

I would have rejected that one!, all of the 40mm PST's that I have owned gave far better images than that. I think the GONG solar images are a better representation of what can be seen with a good 40mm on a good day. 🙂

The cladding is a very recent addition, the blocks are a decade old and were showing signs of degradation due to wet and frost. 🙂

Yes, in West Yorkshire where heating is not much of a problem! 🙂

Hello Dan. I have built 3 block observatories and 3 block telescope housings with no apparent problems. I have clad the exteriors with white plastic soffit strips for added weather protection and appearance. 🙂

It looks to me as though the light coloured focus tube is a sliding fit. The three bearings outside the main telescope tube are probably offset such that when the outer collar is rotated it will move the focus tube in or out. If the telescope was posted, the focus tube was probably pushed right in by the packaging. 🙂

The scope or the young lady shopper? 🙂

Put some wheels on the base and drag the complete thing to your observing site?. 🙂

I have a similar setup. I made the binocular a couple of years ago following a post on CN asking why was there no small angled binoculars. I had enough bits to build one so thought why not?. I was amazed how good they were considering they were pretty cheap binocular objectives. Unfortunately using high grade components soon racks up a considerable outlay. I've often been tempted to use a pair of the 50mm SWED guide scopes, but again, the cost! 🙂

Whilst achromats can give excellent visual results, the long focal ratio needed to do this makes them unsuitable for imaging DSO's compared to apochromats even in narrow band. Triplet apochromats, by their nature, are expensive items and tend to be made to a higher specification. 🙂

Once the polar axis is aligned satisfactorily that should be it unless it is subsequently disturbed. Slight differences in assembling the telescope shouldn't matter, it's the polar axis of the mount that's aligned, not the telescope. 🙂

We often visit libraries to give illustrated talks and usually take along a telescope, a solar one if the weather is suitable. I'm not sure how much night time observation would be possible. In any event, just seeing the telescope raises interest. I'm pretty sure there is no collimation facility for the primary mirror on the 100P although unscrewing the lateral screws that hold the complete mirror cell allows some adjustment by push- pulling manually and then retightening. 🙂

The 200 Dob is the default recommendation, not because it's necessarily the best telescope but certainly the best value. Personally, I would advise a beginner to spend nearer £500 than £2500 as at this stage it's usually unclear in which direction the interest will lead. I also think it's best to avoid too much compromise by trying to mix visual with imaging as it involves very different priorities. To sum up, I would advise something like a 200 Dob for starters to be followed eventually by replacement or adding to by something dedicated to a particular interest. Welcome to SGL. 🙂

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