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TAL-tastic! Another 100RS...


Planetesimal

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Regarding caps for the eye lens side of Tal Plossls.

I find that a cap of 37mm I/D* to be a perfect snug fit over the rubber eyeguard(Perhaps also other manufacturers of a similar type). You can pick the eyepiece up by the cap, give it a right good shoogle and it stays put.

Off the top of my head here a couple of US based suppliers..........

http://agenaastro.co...umq4hhetj5upuc1

http://www.scopestuff.com/ss_eyec1.htm

I'd like to think that there's someone closer to home that stocks this size. I'd like a couple more. Anyone?

Andy.

* Cap has '37', marked on the inside of the cap. I measured to double check.

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I don't know if the 32 & 40mm Tal Plossls have the same sized barrel at the top. Never had those focal lengths. But a 37mm I/D cap should work for the 6.3 - 25mm range. Do check yours, just in case I've got something freakishly different.

Forgot to mention............. the above is for the more modern Generation III plossls. The Gen II eyepieces were, 42mm Kellner, 25mm Plossl, 15mm Kellner and 10mm Plossl. Different body shape and a std 31.75mm cap fits them.

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Great scope the Tal 100RS, im always glad to see another new owner doing the traditional unboxing ceremony, he he!

I tried the new Baader Classic Orthos in mine (#0095) last night on Jupiter and M42, wow, very nice views indeed. A good match up I think!!

Clear skies

Doc

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Thanks Andy, I'll have a look and see if I can get some spares and let you know if I succeed! My GSO 32mm cap fits both the TAL 6.3mm and 25mm incidentally. I think the cap needs to be reasonably big to contain the eyecups when they're folded down.

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I've just been lining up the finder using a telegraph pole over in the back field. I found lining it up a little bit more fiddly without the "spring" you get in the SW design, but it did work and I was able to line up the main 'scope perfectly, increasing magnification all the way from my 32mm GSO up to the TAL 6.3mm. I have to say AB is spot on about the quality of the focuser. It's really a lot better quality optically and nicer to focus than my SW 9x50...

Funnily enough looking through the EPs in daylight, the fine grain of the wooden telegraph pole was noticeably sharper and more contrasty in the TAL 6.3 than in the BST 8mm, although let's wait for a fair test on the night sky... With the help of the crayford I was able to resolve the branches in the bramble hedge to perfect clarity and sharpness - there was a little purple and green fringing around the edges from CA, but that's to be expected in full daylight!

I did find the outer edges of the fov in the BST just warped in and out of vision - I'm guessing eye relief being the cause. The 6.3mm really requires a bit of squishing your eyeball against a pinhole - but that's a hazard of older designs of high mag EPs I think, you only have to look at the flat top ortho design you get with the BGOs.

There's defintely some dust on the inside of the objective, from looking down the tube... I'm wondering if I can use my Baader optical fluid on the objective - does that sound reasonable? As far as dust on the inside goes, I'm tempted to just leave it. I'd rather not start messing with the front lens element at this early stage if I can avoid it.

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Andy,

I have the 6, 10 and the 18mm BCOs. John's initial review on then tipped me over on the decision to get them or not!

I was a little worried about the smallish FoV of the BCOs, as ive had a few Naglers in the past and they were simply fantastic! But, now ive had a short play with them, in my Tal 100rs, im blown away with the views, very sharp indeed!

Very impressed with them to be honest and I am amazed that you can obtain this kind of performance for not too much financial outlay!

Doc

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Thanks Andy, I'll have a look and see if I can get some spares and let you know if I succeed! My GSO 32mm cap fits both the TAL 6.3mm and 25mm incidentally. I think the cap needs to be reasonably big to contain the eyecups when they're folded down.

Yeah, the 37mm I/D cap basically pushes on and folds down the eyeguard, pushing it against the barrel top. Snug as a bug.

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Andy,

I have the 6, 10 and the 18mm BCOs. John's initial review on then tipped me over on the decision to get them or not!

I was a little worried about the smallish FoV of the BCOs, as ive had a few Naglers in the past and they were simply fantastic! But, now ive had a short play with them, in my Tal 100rs, im blown away with the views, very sharp indeed!

Very impressed with them to be honest and I am amazed that you can obtain this kind of performance for not too much financial outlay!

Doc

Interesting to hear that you like the BCOs Doc, I've been reading John's review as well... With my 6.3mm plossl the max mag I can get at the moment is nearly 160x, but to really push the limits I'm going to need a 4mm (and of course a 5mm to bridge the gap!). I was disappointed to hear the BGOs were discontinued, but if the BCOs work well I might just have to give them a try!

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I was disappointed to hear the BGOs were discontinued, but if the BCOs work well I might just have to give them a try

Or hang in there. I know it is a rarity but the BGOs do crop up from time to time on the secondhand market and once obtained I figure they're keepers. I mean, with the trend toward widerfield, they might well be the last high-class Orthos manufactured for quite some time.

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Andy,

I have the 6, 10 and the 18mm BCOs. John's initial review on then tipped me over on the decision to get them or not!

I was a little worried about the smallish FoV of the BCOs, as ive had a few Naglers in the past and they were simply fantastic! But, now ive had a short play with them, in my Tal 100rs, im blown away with the views, very sharp indeed!

Very impressed with them to be honest and I am amazed that you can obtain this kind of performance for not too much financial outlay!

Doc

I'm glad you are enjoying the BCO's Doc :smiley:

They are simple eyepieces in design and execution but very effective.

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Right then, rather than start a new thread, here's a summary of my first light experiences with the 100RS, observing from my back garden which has fairly unobstructed views from 245o SW to 65o NE. The seeing wasn't great and my local light domes were more obvious than usual with a lot of light scattering in the south west part of the sky in particular. Another clue to the low transparency was the absence of discernible detail in the Milky Way, so I wasn't expecting to be pushing the TAL to it's optical limits - and I wasn't wrong!

However, it turns out my first night alone with the TAL was more of a voyage into the challenges of amateur astronomy than I expected, so rather than giving a detailed review of the (already well documented) frac's capabilities, here are some of my "observations" from night one:

Observation no.1: Refractors are not the same as reflectors! Since last night I've come to think of these different scope types as akin to different musical instruments. It's like being able to play the flute and thinking you can pick up an oboe and just start playing... I've realised that the last 4 months owning and using my newt at every opportunity has enabled me to fine tune the instrument and my skill in its use to some extent - picking up the TAL was like starting from scratch. The slow-mo cables were on the wrong side of the mount resulting in some unplanned night yoga, I had to keep rotating the diagonal out of the way of my head to use the finder, and I spent about 10% of the time sitting comfortably in a nice garden chair looking through the EP and the rest of the time crawling about on the frozen ground, twisting my neck and crippled with pins and needles. In short, I've learned that I've got a lot more to learn before I can truly get the best out of the TAL! :grin:

Observation no.2: I had some initial challenges - most of which were down to my lack of frac experience as I've mentioned above... However I did manage to make some observations:

I learned that refractors do need cool down time. My first target was Jupiter because I wanted to check out the contrast and CA, but initially views were boiling, fringed with purply green CA and essentially featureless. After about 15 - 20 minutes equilibrium was reached and the planet was crisp with no evident CA and all bands present and correct. Contrast wasn't fantastic but as seeing was below average that's no surprise... I'll have to wait for a sample greater than n=1 to decide whether it beats the 150PL! I will say that despite the poor seeing, in comparison with the reflector, I found the view of Jupiter was very 3D (particularly through my 8mm BST) - by which I mean it was immersive. I actually started to feel slightly vertiginous, like I was floating in space, approaching the planet in a space craft of some kind.

What's been said about the TAL plossls was pretty accurate. The 25 mm was great - dark background sky, no discernable CA, pin sharp stars, good fov. The 6.3mm was a different story, too dark with poor contrast and hard to focus (however I think this will be partly due to that bad seeing again).

Another aspect of the TAL's performance is the quality of the crayford focuser... Lovely to use and way easier to get perfect focus than the SW R&P I'm used to. Stars (and Jupiter's moons) were resolved to pin points which was brilliant, really compelling to see the stars "as they are" rather than riddled with the various diffraction artifacts you get with the secondary obstructions of the newtonian design. I had some initial challanges with the crayford though - as soon as the 'scope was pointing up more than 45o the whole focuser drawtube kept sliding right out to its full extent, making maintaining focus impossible. I managed to get it sorted after a few tries by fiddling about in the dark with the two screws under the focusser assembly. Once that was fixed focusing was a dream.

Observation no.3: So, I was determined to road test the TAL on a range of targets. Having checked out Jupiter, I took in the Orion Nebula (nice sharp trapezium in low through to high mag, and obvious nebulous structure with the bulk features clearly visible), 4 galaxies (pleasingly the pair that make up the whirlpool in Canes Venatici were as bright as seen in my reflector, plus the two Messiers in the Leo triplet - the NGC of the trio was too faint which may have been due to limitations in the 'scopes light gathering power although I feel the seeing didn't help), and 4 open clusters (Beehive, Pleiades, M36 and M37 - Auriga was near the zenith so my neck gave out before I got to M38!). All were bright, and very nice to look at, particularly the clusters which showed an appealing depth of field I'm not used to. I was very happy that the TAL can cope with a good representative sample of targets - I had planned to try splitting some doubles but visibility had deteriorated so this will have to wait until second light.

I think I'm going to need to make a few modifications to improve observing comfort though - I'm sure others have their own ideas, but I think I'll be getting a spare riser base to attach my telrad. I like the TAL finder a lot but I struggle with the straight through style, being used to my RACI - not sure how to fit one of those on the TAL though, I don't fancy drilling the OTA! A bit further down the line I think a 16" extension pier for the mount would be a good move as well... Overall I'm really pleased with the TAL so far, it looks, feels and performs like a precision scientific instrument - sometimes I think of all the investment in time and money we put into generating these tiny images in the eyepiece, then I remember the hard work these telescopes have to do, collecting photons from entire galaxies millions of light years away and in the past, that most humans who have ever lived have never seen or are even aware of, where maybe beings like us are looking up and thinking the same?

As a final thought, I'm finding that the amount of cloud we get does impact my ability to relax properly when I'm out observing. There's always the fear that a cloud bank will roll in and that's it for a month, which means it's hard to relax and just look - I'm always wanting to hop on and look at something else, which means I don't get the chance to really absorb the detail in all these wonderful objects. I'm starting to see the appeal of sketching what you see at the EP... the way it forces you to really take your time over an object and get to know its nuances and character.

Well, that's all for now, back to normal life, until next time! :smiley:

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Great stuff....gald to see another 'TALurian......'

I too found viewing angles to be a bit like playing 'twister' at times :grin: but great times. Recently got the RS...and an older R...and I did find the R view edged the RS slightly in terms of contrast....but could have been the seeing on the two differnet nights..Dont have time to change them over as afraid to loose the sky to bunch of marauding clouds! The focuser on the RS is a lot nicer though.

I am going to have to seriously look at those BCO's...time for a shopping list I think...and a Nebula filter... :grin:

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I had to keep rotating the diagonal out of the way of my head to use the finder, and I spent about 10% of the time sitting comfortably in a nice garden chair looking through the EP and the rest of the time crawling about on the frozen ground, twisting my neck and crippled with pins and needles.

I think for many this is a general problem with fracs; uncomfortable observing positions. As you mention, something like an extension pilar might help. I've also heard that purchasing an adjustable ironing chair is a great aid.

I think I'll be getting a spare riser base to attach my telrad. I like the TAL finder a lot but I struggle with the straight through style, being used to my RACI - not sure how to fit one of those on the TAL though, I don't fancy drilling the OTA!

As you can see in the photo, a Telrad has been tied to the OTA with plastic zip ties and it worked fine. These ties are handy because you're not compromised by any degree of permanency. I also placed under the Telrad's baseplate two strips of denim, to cover the Telrad's own glue strips. These glue-strips were still protected by the plastic covering but I did find that a degree of 'gunk' from them oozed onto the OTA.

Out of interest, nowadays I don't really bother with the Telrad in a 'permanent' set up on the Tal. When needed, I just hold it onto the tube, line up with some faint and tricky star and from there go onto the 9x50 for star hopping.

On the other side is a 9x50 finder which is kept on place with only the one screw and a little patch of denim underneath the shoe. This acts not only as a protection to the OTA but gives a really firm support. No drilling needed and I have a 100% solid foundation.

taltelvf.jpg

I'm finding that the amount of cloud we get does impact my ability to relax properly when I'm out observing. There's always the fear that a cloud bank will roll in and that's it for a month, which means it's hard to relax and just look - I'm always wanting to hop on and look at something else, which means I don't get the chance to really absorb the detail in all these wonderful objects. I'm starting to see the appeal of sketching what you see at the EP... the way it forces you to really take your time over an object and get to know its nuances and character.

Ay, the Spanish have a kind of expression for this dilemma, 'cada uno con su problema' :smiley: You guys are troubled by clouds, over here I'm troubled by chronic LP and so on. In a way they are similar disabilities, for one way or another they prevent us from seeing what we'd really like to be seeing and can be insidious roots towards frustration and anger.

I personally feel it is better to be a space-visitor, rather than a space-tourist. Folk go to a museum, for example, and will try to rush all the paintings, but at the end of the day, they only remember at best one or two of them and not that well either and the same analogy could be used when stargazing.

I will try to spend an entire evening, say, with just Jupiter and perhaps a double star or two. Or I will spend an evening with the Moon and an Open Cluster. Another night with just one constellation, hopping between the stars. Galaxies, Nebulae, Globs etc are just out of the question with the small 4" in a city. I will always try to sketch at least 2 sights and will go back and swot a little on what I have seen and missed. This, as sad as it may sound, for me, is a great night out.

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....I personally feel it is better to be a space-visitor, rather than a space-tourist. Folk go to a museum, for example, and will try to rush all the paintings, but at the end of the day, they only remember at best one or two of them and not that well either and the same analogy could be used when stargazing.

I will try to spend an entire evening, say, with just Jupiter and perhaps a double star or two. Or I will spend an evening with the Moon and an Open Cluster. Another night with just one constellation, hopping between the stars. Galaxies, Nebulae, Globs etc are just out of the question with the small 4" in a city. I will always try to sketch at least 2 sights and will go back and swot a little on what I have seen and missed. This, as sad as it may sound, for me, is a great night out.

Nicely put and I agree 100% with this approach :smiley:

Time spent studying an object, whether deep sky or solar system, is almost always rewarded with more detail as your eye "tunes in" to the image that the scope is producing. It also enables you to capture those fleeting moments of really good seeing where your optics suddenly show, even momentarily, what they can really do :smiley:

I'm always a bit worried when I see reports like "I managed a quick look at Jupiter but could not see much detail". Study the planet for an hour or more and then more will become visible, sometimes much more :grin:

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Nicely put and I agree 100% with this approach :smiley:

Time spent studying an object, whether deep sky or solar system, is almost always rewarded with more detail as your eye "tunes in" to the image that the scope is producing. It also enables you to capture those fleeting moments of really good seeing where your optics suddenly show, even momentarily, what they can really do :smiley:

I'm always a bit worried when I see reports like "I managed a quick look at Jupiter but could not see much detail". Study the planet for an hour or more and then more will become visible, sometimes much more :grin:

This is how i prefer to do my observing, get comfy, and choose a few targets to find and view for the session, spend some time on each one i find, before going to the next, also regarding having the eyepiece at funny angles, using my refractor on the AZ4 mount, the ep stays at an upright position at all times

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This is how i prefer to do my observing, get comfy, and choose a few targets to find and view for the session, spend some time on each one i find, before going to the next, also regarding having the eyepiece at funny angles, using my refractor on the AZ4 mount, the ep stays at an upright position at all times

Have to agree with this being the best approach for me also.

When I first got back going I was wanting to see as much as I could, whizzing all over the place with the goto. It started feel a bit like watching a film. I got to see everything I wanted but I can hardly remember most of these times in the ways I remember my last 5/6 outings with the dob and frac taking a more leisurely approach and making a bigger effort to learn the skies and trying to become an observer rather than a ticker. Although I will add that with limited opportunities I doubt I will ever get to know the skies like I felt I did when I was a lad. But the laid back approach is far more enjoyable and relaxing.

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