Deadlake

13 minutes ago, jetstream said:

Reflector owners are mesmerized by the view to the point that they kinda forget who made the mirror😀

On the other hand there is much time for debate among refractor owners IMHO

Not which ladder to buy 😀, parrcor options or effect of obstruction... 😆. 

3 minutes ago, jetstream said:

Does it matter on DSO?😀

 

Using an NV EP is not so sensitive to a mirror acclimating.  

By the way whereas the refractor guys like to discuss which brand is best don't the Dob owners like to discuss which mirror is best, i.e. I've got a Lockwood Optics mirror???😄 

Same as having a light green telescope.....

3 minutes ago, jetstream said:

Once healed up and not "draggin a leg"  I can wheel the 24" out in 2 minutes, collimate and view...

How about this?

I'll challenge you to a NV duel- me with the 24" f4.1 -you with the C9.25 and see who gets viewing quicker and sees more!

A 9.25" mirror versus a 24" one, which one will cool down fastest??? Not that you need that so much for DSO's... 😀

14 hours ago, jetstream said:

My offer is still open Mike!

You can view through my TSA 120 and then immediately switch to my 15" and tell me what you see!

I might humbly suggest that if the TSA120 shows more an eye exam might be required!!

But Gerry what are going to see more with your 24" Dob monster or a C9.25 with a NV eyepiece? 😀

I know which one will show more and is more movable and maybe costs less.... 

 I use dark sky meter on iOS, however do not know how comparable it is with the Unihedron.

Given the endless cloudy nights over the winter how many people spent time plotting new gear when otherwise they would be looking up?

But yes, I've bought quite a lot due to forward planning then not going to use it. At the same time I have over spent my planned budget:

Initially went with a scope tech zero mount for light weight use, however now prefer the Vixen SXP2 GEM mount I have now for ease of use.
Original attempted to use a Vixen SLV 2.5 mm EP for looking at moon/planets, now have a full set of Vixen HR's and TOE 4mm.

I did think that a Vixen 103SD would suffice, now have a 130 mm LZOS on order.

There is a trend here...
 

2 minutes ago, PeterW said:

Thursley area looks good, also maybe arbor chiddongford,  woolbeding common, S of Blackdown may also be worth looking for places with the right logistics and views that can then be measured at night.

Peter

Have you got a light meter or using your iPhone to measure. Has @GavStar got one?

8 minutes ago, whooshbang said:

I reckon set up straight out of the boot of the car. looks pretty open and i can't stand lugging kit too far from the motor. Plus i like to keep an eye on the car and use it for a comfy flask of tea. 

I 'm gonna check it out Sunday.

 

I'm might go over sooner, have some stuff for the tip at Milford. I think we have 3 car parks within 5 minutes of each over so will do a drive by.

18 hours ago, Adam J said:

Ok it took me only 5mins on astrobin looking for images with bright stars in them to find a pinched TSA-120. 

https://www.astrobin.com/271304/C/?page=3&nc=user

I did not even get a significant way through the TSA-120 images to find it. Perhapse it was taken at -30c but I really doubt that. 

Just goes to prove that if you go looking for problems on the internet you will always find them. 

 

How do we know what the temperatures where when the photos where taken? I'm trying to work out how you are correlating the image shown to low temperature.

For example why not collimation is an issue? I know what dealer who collimated all the scopes he gets in that have been through QC and that applies from Far East to premium manufactures. 

12 minutes ago, Stu said:

21 is pretty decent. Obviously the higher the better but convenience counts too. Bignor is a bumpy road at the end, and is quite exposed if it’s windy.

We’ve been looking for quite a long time and these two keep coming back, not sure Peter’s holy grail exists..... but like the ‘real’ thing I guess... 🤣

Where is you starting point,  West End Village? Thursley common is around 5 mins more travel time than Ranmoor and the SQM is just under 21, plus the car park you can walk straight out onto a field. Its 5 minutes off the A3.

I'll see how dark its really is.

2 minutes ago, PeterW said:

Dark and close, easier to get one or the other. I’d suggest SQM data unless the app has been checked to ensure the numbers returned are correct. I’m hopeful we’ll find some sheltered location that is surprisingly good and easy to get to… the holy grail.

Peter

Close in time to travel and distance are obviously not the same. I think there is a location which is south of the A3 around Haslemere, looking a the light pollution maps. 

Near Bignor, the roads are slow out there as noted. I'll keep digging, we after 21.3 SQM or is 21 SQM enough?

The "juant' as you call it is why I was thinking of sites off the A3, as the its pretty quick to get away from London.  

As soon as you get on the road to Petworth the roads are not as fast. 

29 minutes ago, PeterW said:

Would be good to collate sites between sw London and the South Downs park (which has been fully SQM surveyed), so we can identify closer dark places. SQM data is best to allow for comparisons.

Peter

Collate sites and maybe ground truth, e.g. iPhone app?

If you following the map down you need to get to south of Chiddingfold to get to over 21 SQM, which would will give new targets to see.

Not tried Hankley common, but planning on looking at south of Haslemere as the SQM gets to around 21.3 and its 30 minutes from where I live.

Hankley is a little closer to me, so maybe a good idea to give it a go as well.

19 minutes ago, Adam J said:

And I just decided to go hunt for LZOS too incase people think I am attacking Takahashi. This is the second image of M45 I checked. 

https://www.astrobin.com/389995/?nc=all

The above temperature ranges are the manufacture specs…

Nice pictures Gavin as always.  Surprised you have not got one of these yet at 140 mm over 100 mm. 😀

15 hours ago, Adam J said:

I think it's ok to expect no pinching at 0c but -10c?

Takahashi are ok to -25 oC, APM LZOS lower and TEC and AP being oil based,  I think around -20 oC from memory.

I'd expect most scopes to work for AP usage to work at -10 oC given  it will be left out over night for image capture on those clear winter nights (well not this year😀)  

1 hour ago, jetstream said:

Well the TSA120 ota is a bit heavier-but- I cheat when mounting it. With the rings and dovetail the SW120ED is really close to the bare TSA120 ota.

So, about my cheating... I mount the superb Tak clamshell with the ADM Losmandy plate on the mount first and open the clamshell. I then put the TSA120 in the clamshell and close it- super easy for me even now. I didnt get the TOA130 because of its weight, about 27lbs.

The Tak 120 is easier to use with its clamshell than the SW120ED and Vixen dovetail-but- this is just my opinion. There is night and day build quality between the 2 scopes.

The TOA-130 takes an age to cool down for maybe some of the best views, excellent colour correction. And it's super heavy, so you would not be carrying that across a farm in case of a slip up... 😀

This thread comes down to are you prepared to pay a premium for a 10% performance delta or need high magnification. 

Actually as noted the premium APO's can provide a larger magnification, but at the same time cannot overcome aperture for limiting magnitude of whats viewable.  

All have trade offs.

22 hours ago, jetstream said:

My SW 120ED will go 350x on the moon and then breaks down- I have not reached image breakdown over 700x with my TSA120. Not sure of the exact mag as I barlow the Vixen HR2.4mm but I'm thinking about 750x sounds right give or take (field stop location).

The build quality is excellent as is the stock focuser, once learning how to adjust it- zero image shift.

So to me yes its worth it.

ps the transmission this scope has is extremely good and proven on very faint nebula.

How much does the weight different between the SW120ED and TSA120 (which is the lightest 120mm APO I can think off) make a difference to which one to use?
One thing about either the of the Japanese brands Takahashi or Vixen is there are lighter than other brands. 

10 hours ago, RugbyRene said:

I do like the Avalon M-Uno. It looks really nice and removing the need for a meridian flip is a big draw. I've had so many imaging nights ruined because the flip failed for any number of reasons.. Did you do any tuning to get such a low RMS? Say a PEMPRO session or adjusting the belts etc.

I'd be interested to know how guiding worked for belt and harmonic drive mounts, they have a larger periodic error and so need a different approach, presume thats need to be guided????

Automatic meridian flip is also assume have it on my SXP2 mount as well. 

I'm surprised that Takahashi have not entered this area as the FSQ range given its speed is well suited for NV and Mewlons as well where a long focal length is required. 
 

13 minutes ago, alex_stars said:

The FPL53 triplet version of TS (and Tecnosky) has a temperature compensated lens cell which can be fully collimated:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p7717_TS-Optics-PHOTOLINE-130-mm-f-7-FPL53-Triplet-Apo---3-7--Auszug.html

as does the FPL53 doublet I have:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10133_TS-Optics-Doublet-SD-APO-125mm-f-7-8---FPL-53---Lanthan-objective.html

The dealer I got mine from (not TS directly) told me that these TS scopes are easy to collimate and he prefers the collimation mechanism of the TS (and Tecnosky) over ES for example....

Also the new FPL55 triplet is fully adjustable:

https://www.teleskop-express.de/shop/product_info.php/info/p12851_TS-Optics-CF-APO-130-mm-f-7-FPL55-Triplet-APO-Refractor-with-Certificate.html

So collimation should not be a problem on any of those.

If these scope where as fast as F6 I'd give them a look, shame they are not. A reducer does not work for my use case.

I do look forward to the reviews for the Triplets as I suspect they will start to get close to the premium makes. 

Also the difference between FPL55 and FPL53, if figuring the FPL55 maybe we will see that, interesting...

5 hours ago, petevasey said:

Hi, Olly and thanks for your interest.  Also well done getting that AZ jab when you did.

Anyway, I absolutely take on board what you (and 'Deadlake') say.  As you would see if you followed my link, mirror cleaning on my RC is straightforward and often never needs any attention to collimation after reassembly.  The only thing that hampers collimation is the generally poor seeing here - even using Metaguide to smooth out the oscillations I still find it very difficult to get the main mirror spot on.  But at the moment I think it's very close.  So 'If you have a high resolution rig which works', well, yes I have although with a smaller central obstruction maybe the resolution could be bettered.

The main thing is the weight.  Although at 16 - 17 Kg it's not desperately heavy, but it's very tricky getting the dovetail aligned then holding the scope with one hand while I tighten the clamp screws with the other.  When I had my 12" Meade ACF, it used tube rings.  They were easy to fix first, then I just had to lift the tube onto the rings where it would sit on its own while I clamped the rings.  It was of course 3 m focal length, but often I used a reducer simply because the seeing wasn't good enough to use the full fl.  It also had intermittent oval stars which I never really tracked down, and the focuser would sometimes slip.  None of that now 🙂  But since I sold my business and retired, almost 20 years ago now, and stopped throwing 25 Kg bags of plastic around, my upper body strength has deteriorated considerably.  25 Kg now is HEAVY!!

Never mind, the gym has reopened and after another week to ensure full protection from my second AZ jab, I'll be going back there.   So maybe things will improve a little although at my age reversing muscle loss is not easy😬

Keep well,

Cheers,

Peter

My question would be can you build an observatory? 

I think the GSO 10" is under rated, particularly the new version where the focusers and body are not linked.

If you have a Tak collimation scope then the main complaint about this scope goes away.

GSO optics are pretty good really. Particularly for the price. ASA (who are extreme quality) tested the bigger GSO RC’s and confirmed as much. The mirrors are quartz which makes for very low expansion so cool down is very minimal unlike the Pyrex mirror of a Celestron. The GSO coating is also very good and very uniform. Its near 100% from 4-700nm and then tails off a bit.

The mirror coatings are a hard dielectric coating. I would assume aluminium but I don’t actually know. 

From whatI’ve been told the GSO mirrors are better then the EdgeHD, you might need to go up market to get a better Astrograph, maybe a planewave, however same time you want lower weight.

The corrector on the SCT still need cleaning , just because it’s sealed does not mean no maintenance. 

Only plus I can see is weight saving.

Markus has posted an update here:

https://www.cloudynights.com/topic/758189-new-apm-zoom-eyepiece-77mm-154mm-75°-constant-fov/?p=11034801

However in another part the price for the astro version is now €395. In the US I guess an extra 20% on top that and more for the UK as well due to Brexit, but maybe just another 4% tariffs.