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Mars with TV76 and Zeiss prism


Stu

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This is a bit of an observing report, combined with some feedback on a few bits of new kit I've got.

Having managed not to throw a tantrum during a (to me) marathon shopping trip to Kingston complete with 5 week old, I think I had racked up enough brownie points for a bonus observing session :-)

Just a quick one though, so decided on the TV76 on the Mini Giro/AT413 but wanted to try out my new 2" Zeiss Prism. It's a lovely piece of kit, and nicer now I've swapped the compression fitting for a ClickLock. I also fitted the VIP Barlow in x2 config which fits within the Clicklock housing and attaches to the 1.25" adaptor so you really can forget about it completely.

I was going for simplicity, so just used 7,6 & 5mm BGO's and Hutech eps, with the Neodymium filter fitted to the 2" barrel of the prism.

First, and main target of the night was Mars, of course. Using the 6 and 5mm orthos, at x160 and x192 respectively, the view was surprisingly crisp and with nice detail. The polar cap was clear, as was Syrtis Major, the frosting over Hellas and what is I think called Utopia, the dark area around the polar cap. What was nice was the reduced level of scatter around the planet, improving the contrast over the Everbrite I normally use in this scope. Positioned just outside the view, there was no sign of Mars so this shows very good control of scatter and internal reflections.

I checked Calsky for a representation of Mars in a 3" scope, and must say the images I was seeing were clearer and specifically crisper than that shown, nearer that for a 4 or even 5" scope but the shading was not as dark. The polar cap and Hellas were very clear and bright. These are a couple of screen shots basically showing the details visible. The basic shapes shown below were visible rather than all the fine detail, polar cap clear though.

huzejypy.jpg

dyhenema.jpg

It was a similar story with Jupiter, excellent control of light scatter and a nice crisp image even at these high powers for such a small scope. Jupiter itself was showing a somewhat quiet side, but still the belts were nicely defined, and moons very crisp, nice to see Io and Europa close together.

Having the Barlow always in the prism does make life easier if you are doing higher power viewing, it eases the eye relief on orthos and as far as I could tell has no negative impact on the view.

I had a quick whirl around a few doubles, all of which looked beautifully crisp, such lovely star shapes. Mizar, Castor, Izar and PI1 Bootis. Lovely colour particularly in Izar.

So all in all a very nice little session. It shows that meaningful observation is possible with small, decent quality scopes, and I'm pleased with the recent additions to my kit. I look forward to trying them in the Vixen :-)

Cheers,

Stu

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Very interesting report Stu - shows what a small but high quality instrument can do. If the diagonal showed improvements over the Everbright it must be good indeed - the Everbright is the best diagonal I've ever used.

Where can one get hold of the Zeiss prism diagonals ?

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I'll do a proper side by side when I get a chance John, not an 'Alan Potts Special', but hopefully with some valid comparisons. My first impressions tonight were definitely favourable and allowed me to use magnifications I had not previously achieved with the TV76 whilst maintaining clarity.

It's not a cheap bit of kit, but potentially worthwhile certainly for planetary work. BillP's review backs up the performance advantage over most mirror diagonals.

I got mine from TS, although Widescreen Centre potentially do them, possibly others. The prisms are in relatively short supply I think so there can be a lead time. I ordered a Zeiss T2 version back at the beginning of Jan but the delivery date kept slipping so I ordered the 2".

Stu

EDIT just to add, you can see the quality just by looking at the prism, it's actually quite hard to see it at all compared with a mirror. One benefit is that the angled reflective surface is internal so will not get dirt or dust on it, whilst the entrance and exit surfaces are easier to clean (if needed) than a mirror.

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Nice report, Stu. We had a look at Saturn and Mars in our ED80 the other night and the image scale was fine and it's got us wondering what would be possible with a TV-60, 76 or 85. Good enough we suspect for some very pleasing quick sessions, even on planets. It could double up possibly as a great compact white light scope for Sarah to use with a Lunt 1.25 Herschel wedge.

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Thanks Luke. As you may know, I probably use the 76 as much for White Light solar with the Herschel Wedge as I do at night. The views are lovely and the whole feel of the scope is just so solid and something I love using. Mine is an older model with the single speed R&P focuser and the lovely focus wheels, perhaps not as fine adjustment as a dual speed ones but it is buttery smooth and I think I prefer it.

I bought mine to replace a WO66, and it is certainly a step up from that, better control of CA and the extra aperture is noticeable in terms of brightness and resolution. Whilst I could see shadow transits and GRS with the 66, it is easier with the 76. The only downside is size and weight.

I did nearly buy an 85, but am glad I missed out on it now. It is a better scope I'm sure, but just that bit bigger and I was looking for portability high up on my requirements list. This is the balancing act you will need to juggle between 76 and 85; size, portability and mounting requirements vs performance.

I can highly recommend my Induro AT413 tripod aswell, really stable and works very well with the PST and 76 side by side.

Gosh I'm going on a bit!

Cheers,

Stu

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Thanks for the thoughts, Stu, much appreciated :smiley:

We're thinking the 76 is the favourite at the moment, the 85 is partly tempting because of more aperture for not too many more £££'s, but we like the idea of the extra portability of the 76.

Edit: I also like the idea of buying scopes from a company with great customer care. I get the feeling that's the case with Tele Vue. I am not too happy with a certain maker of scopes at the moment, I feel like they couldn't care less about me!

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Thanks for the thoughts, Stu, much appreciated :smiley:

We're thinking the 76 is the favourite at the moment, the 85 is partly tempting because of more aperture for not too many more £££'s, but we like the idea of the extra portability of the 76.

Edit: I also like the idea of buying scopes from a company with great customer care. I get the feeling that's the case with Tele Vue. I am not too happy with a certain maker of scopes at the moment, I feel like they couldn't care less about me!

The great thing about Televue is the scopes are very ruggedly built and designed to be serviced or repaired. They seem happy to give advice on sorting out scopes which have been bought second hand, and you can ship scopes back to them for servicing. I have spoken to them a couple of times in the phone and they have always been very helpful, David Nagler himself on one occasion.

Stu

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