First Light on "Classic" ToPic 80mm f15 (Towa 339)

[SuburbanMak]

A few decent breaks in the cloud last evening sent me scurrying into the garden to get first light on my "new" ToPic 80mm f15. There's always a bit of trepidation when trying out an eBay purchase but the first view of the quarter moon with a 32mm Plossl immediately set this to rest - this is one optically sharp 'scope! 

Seeing was quite mixed low down, steady toward the zenith. Transparency 4/5 in the genuine gaps between clouds but a lot of misty stuff moving through in the meantime! EPs used were 32mm TS Optics Plossl & 18mm, 10mm & 6mm Baader Classic Orthos. 

I used the moon to align the finders (dreadfully fiddly solution on scopes from this era and this example is no better, although the finder itself is a crisp 4 degree FoV 6x30 that would accept other .965 EPs) and then went back to the main scope to test. First thing to note was that there was to my eye no discernible CA at all up to 120x.  With the 6mm BCO at 200x there was the slightest red fringe on the lunar limb (and I mean slight as in a very narrow band), the Moon was quite low so this could be more atmospheric, either way no real problem there. Was able to achieve reasonable focus on the terminator at 200x and could see that with better seeing this will be a usable power. At 120x I was getting drawn into the textured detail of the highlands S of Mare Vaporum and sharply defined Ryma Hygnius. Ptolemaeus & Herschel (I think) looked great on the terminator.  Also watched the crater Bessel, a sharp 15km feature in Mare Serenitatis, bobbling in and out of focus with the seeing. Most striking of all was the brown/slate grey colour contrast between Mare Serenitatis and Mare Tranquilitatis - the best I've seen this outside of photos and much more noticeable than in my five inch Mak.  

Next I trained to Jupiter just a few degrees above the moon last night (the two made for a really atmospheric sight naked eye with an aircraft con-trail snaking between them).   Seeing was bit "boily" but I could see immediately a very clean contrasty image with good colour, the 2 equatorial bands always present and others coming & going. Sweet spot was 120x last night & the scope was pairing very well with the 18mm & 10mm BCO. I can see that on the right night this is going to be a superb rig for pulling out planetary detail.  It felt like the Galilean moons were tiny discs, need to look up if this even optically possible at this aperture but still, a lovely view. 

On to Saturn and considering how low its getting this was an amazing view - Cassini division clear in all but the worst seeing bobbles, banding on the disc better than I've seen it in the Mak 127 and I thought some darkening at the pole.  Crisp shadows of planet on rings & rings on planet and 3 moons with direct vision and a sense of more in AV.   Could have stayed here all evening but wanted to look a few stars and the gaps in the cloud were getting further between...

Vega - to do a rough star-test, and very pleased to see nice almost-perfectly-round rings either side of focus. There is the slightest hint of a top to bottom oval - the lens cell does have collimation screws but given how close this is I'll probably leave well alone given my zero experience in this area!  (Ditto the light film of dust on the inner face of the objective lens - lens cell thread is currently jammed anyway so was pleased this didn't seem to impede viewing much).  Did the same on Capella and Aldebaran too for fun and enjoyed the rich colours. 

Almach - presented beautiful airy discs and diffraction ring on the primary and a nice green ball secondary in the 18mm BCO 67X. Lovely view. 

Polaris - the 18mm BCO showed the secondary with AV, not quite the view I might have expected. 

Epsilon Lyra Double Double- ditto Polaris really, good split of the easier pair at 120x but can't claim to have split both.   Look forward to testing properly on doubles on a night of good seeing, 

Pleiades- beautiful view against an inky background in the 32mm, the main group just fiitting in the FoV, this tallies with astronomy tools confirming the max field as being just over 1.3 degrees.    

Gathering cloud and heavy dew ended the session. 

There are some logistical downsides & some work to do - its a very long tube and the rough-focus pull-out draw tube has to be a fair way out to achieve focus.  (If anyone knows where I could get a 200mm long 36.4mm tube with a male Vixen thread at one end and a female at the other, or a few shorter extenders threaded togther I would love to hear from you!).  

My solution for marrying the 1.25 inch diagonal to the drawtube is currently not as secure as I'd like (nosepiece from an SW diagonal screwed into the drawtube clamped to the diagonal using a 2in-1.25 inch EP converter that came with a TS Optics focuser. Currently looking at options including plumbing fittings! 

Manoeuvring down the garden on the tripod is not something I'll repeat - its a two-trip setup. 

To reach the Alt clutch on the AZ GTi I need Mr Tickle arms. Also at anything above about 45 degrees even with the Berlebach 312 fully extended I could do with a low seat to view - maybe a fishing stool...     

I've knocked the baffles out of the focuser tube and painted the inside, I can see that this has delivered the maximum possible FoV but in daylight viewing this had reduced contrast and can still see some light bouncing around - flocking material ordered - the prospect of delivering even more contrast based on this first view is exciting. 

Riding on my AZ GTi mount there is a second or two of vibration after moving or focussing, long term I can see more expenditure on a heavier mount coming (maybe SW Steel tripod & SkyTee - would  welcome opinions on whether this would improve things).   

All in all a very satisfying first light.

By the end of the session the tube was slick with dew, I wonder if people ever fit handles to these things...

 

 

 

 

 

Edited November 12, 2021 by SuburbanMak

[ScouseSpaceCadet]

Great report demonstrating astronomy doesn't need to be mega expensive. 😀

Regarding the AZGTI, I doubt the steel tripod would improve the vibes at all compared to your wooden Berlebach. If you haven't already upgraded, then an AZGTI ADM saddle may help but the scope is probably just way too long for the AZGTI. I imagine a SkyTee or similar would work out just fine if you're happy losing the goto and tracking functionality.

 

[SuburbanMak]

59 minutes ago, ScouseSpaceCadet said:

Great report demonstrating astronomy doesn't need to be mega expensive. 😀

Regarding the AZGTI, I doubt the steel tripod would improve the vibes at all compared to your wooden Berlebach. If you haven't already upgraded, then an AZGTI ADM saddle may help but the scope is probably just way too long for the AZGTI. I imagine a SkyTee or similar would work out just fine if you're happy losing the goto and tracking functionality.

 

Thank you.  I have the ADM upgrade & a PB70 Az puck to use the mount manually (my one worry with the AZGTi is a flimsy Az clutch, better locked and left that way). 
 

Good intel on the tripod & you are right, I’d particularly miss the tracking function which given my growing collection of pea-shooters is a very useful feature indeed! 
 

I agree that it’s a bit too long for the mount, magnifies the very slight Alt play in the gearing. Works for now though & may well be better with the AZGTi in powered mode.  I’ll post when I’ve tried that. 
 

 

Edited November 12, 2021 by SuburbanMak

[ScouseSpaceCadet]

1 minute ago, SuburbanMak said:

Thank you.  I have the ADM upgrade & a PB70 Az puck to use the mount manually (my one worry with the AZGTi is a flimsy Az clutch, better locked and left that way). 
 

Good intel on the tripod & you are right, I’d particularly miss the tracking function which given my growing collection of pea-shooters is a very useful feature indeed! 
 

I agree that it’s a bit too long for the mount, magnifies the very slight Alt play in the mount. Works for now though & may well be better with the AZGTi in powered mode.  I’ll post when I’ve tried that. 
 

 

If the goto and tracking will be missed, maybe splash out on a used EQ5 class mount? I haven't looked back since essentially being forced to upgrade from an AZGTI to a used Celestron AVX. The f7 ED102 was just a bit too heavy & long for the AZGTI. On the AVX it's a toy. Rock solid. Setup takes an extra few minutes. Observing positions are comfortable to. I just rotate the diagonal. Bear in mind though,  Celestron do not sell an extension pillar to fit so not a good choice for long focal length fracs...

There's a decent 80mm f15 refractor thread on that other forum...

https://www.cloudynights.com/topic/797543-80mm-f15-refractors/

[Louis D]

Try putting some vibration dampening pads under each tripod foot.  I found that vibration dampening went from 2 to 3 seconds down to a half second with them.  This was with my rather solid DSV-1 mount on a Manfrotto tripod and a 72ED scope.

[philj]

Glad your impressed with the Tooic/Towa. I still use mine regularly, clouds permitting, and always enjoy the crusp views. A well set up Towa 339 gives excellent views. I got rid of the focuser on mine, fitted new baffkes, ota extension and a 2" focuser. It works superbly with  modern eyepieces.

[SuburbanMak]

25 minutes ago, philj said:

Glad your impressed with the Tooic/Towa. I still use mine regularly, clouds permitting, and always enjoy the crusp views. A well set up Towa 339 gives excellent views. I got rid of the focuser on mine, fitted new baffkes, ota extension and a 2" focuser. It works superbly with  modern eyepieces.

Wow - that’s some conversion! 
I’m actually pretty happy with the focuser - stripped and re-greased it’s smooth and nicely damped, no sign of droop despite the massively long pull out draw tube extension. 
 

What kind of FoV can you achieve with the 2in conversion? 

[SuburbanMak]

UPDATE: I couldn’t let it lie, had to clean that muck off the lens.
The cell succumbed  to a pair of strap-wrenches & the lens cleaned beautifully with an oh-so-gentle wipe with a microfibre cloth and the faintest whiff of Baader Optical Wonder. 
 

Before:

 

After:

Edited November 12, 2021 by SuburbanMak

[SuburbanMak]

1 hour ago, ScouseSpaceCadet said:

If the goto and tracking will be missed, maybe splash out on a used EQ5 class mount? I haven't looked back since essentially being forced to upgrade from an AZGTI to a used Celestron AVX. The f7 ED102 was just a bit too heavy & long for the AZGTI. On the AVX it's a toy. Rock solid. Setup takes an extra few minutes. Observing positions are comfortable to. I just rotate the diagonal. Bear in mind though,  Celestron do not sell an extension pillar to fit so not a good choice for long focal length fracs...

There's a decent 80mm f15 refractor thread on that other forum...

https://www.cloudynights.com/topic/797543-80mm-f15-refractors/

Hmm… some thinking and saving to do! 

That’s a great thread btw thank you. 

[Pixies]

5 hours ago, SuburbanMak said:

There are some logistical downsides & some work to do - its a very long tube and the rough-focus pull-out draw tube has to be a fair way out to achieve focus.  (If anyone knows where I could get a 200mm long 36.4mm tube with a male Vixen thread at one end and a female at the other, or a few shorter extenders threaded togther I would love to hear from you!).  

My solution for marrying the 1.25 inch diagonal to the drawtube is currently not as secure as I'd like (nosepiece from an SW diagonal screwed into the drawtube clamped to the diagonal using a 2in-1.25 inch EP converter that came with a TS Optics focuser. Currently looking at options including plumbing fittings! 

Have you got any pics?

 

[SuburbanMak]

14 hours ago, Pixies said:

Have you got any pics?

 

There are two focus tubes. The drawtube is a 36.4mm (Vixen threaded) chromed tube on which the focus rack is mounted. 
Sticking out of the drawtube is a long 1.25 inch chromed tube. 
Ideally I’d replace the 1.25 in tube with additional length at 36.4mm, I have a Vixen-1.25 converter I can use to hold a 1.25 prism. 

[SuburbanMak]

Conversion to 1.25 now complete, baffles knocked out of draw tube and flocked. Chrome waste-pipe connector functioning admirably as an eyepiece holder. Dew shield flocked for good measure.  
Have also treated it to a Baader Sky Surfer RDF - the original finder though optically nice is just awful to align. 

All of which guarantees continuous cloud cover! 

Edited November 20, 2021 by SuburbanMak
Grammar

[SuburbanMak]

A bit windy last night & Jupiter was rubbish low down, but enjoyed a short lunar session + am improved star test (it’s that plumbing joint!) and lovely views of Polaris & Almach. 
Took a couple of pics with the iPhone wobbling over the EP…

[SuburbanMak]

Work gave me the day off - making the most of it by squeezing in some solar with the Towa.

Seeing coming & going but a nice detailed view at times of two curved sunspot chains & some texture on the disc. Best view at 67x with an 18mm BCO. 

I can see the Towa being on solar duty a lot. 

Edited November 25, 2021 by SuburbanMak