Deadlake

5 minutes ago, Stu said:

Absolutely! You can always make use of both!

Or should I buy a Dob when I have a refactor and I'll use the Dob three times a year before selling it?
 
I want a reflector for more aperture but I'm concerned I will not use it enough to justify its purchase.

Might just be a summer scope.

5 hours ago, Louis D said:

Speak for yourself.  My TS-Optics (Sharpstar) 90mm FPL-53 triplet APO takes at least 30 minutes to acclimate just 15 degrees F (7 degrees C ?) before stars quit having spikes.  My 8" Dob acclimates in about the same time, but to get rid of blurriness associated with tube currents.  If I put fans behind the primary, I'd probably be ready to go in under 10 minutes.  Low power views are fine in the Dob while waiting.  Not so much with the APO.  Those spikes are still plainly visible on bright open clusters like the Pleiades.

There are numerous threads on these forums about glass or mirror quality. However little reports on how thermal stable or how quickly a scope acclimates.
I find during winter months my Vixen SD103S is ready to go in around 10 minutes with a temperate delta of around 10 oC.
I suspect other manufactures like LZOS and Stellarvue with steel lens cells can keep the same performance but with larger apertures, in the winter I'll find out.  

8 minutes ago, John said:

The best "accessory" for getting more out of astronomy whatever scope you use - retirement 

Working from home helps, on schools days I get up at 8 am. However unlike last year the clouds and the school days are not overlapping. 😩

1 minute ago, JeremyS said:

2 or 3 times a year based on my experience 🤣

I’m lucky to get 2 hours in before being up for work in the morning or clouds stop play… 🤨 Choose a scope for your style of observing….

2 hours ago, Highburymark said:

That was my order from FLO I think. Brilliant though the SW AZGTi and Solarquest mounts are, I’ve had to admit I need something stronger. After searching everywhere, had to conclude there was nothing else on the market that ticked all my boxes. Think there’s room for a beefed up AZGTi-type mount, with a 7kg payload, solar-friendly, that can operate on a robust camera tripod, and be easily packed away for travel.

I’m sure a TSA-120 or maybe a FSQ-106 ( at F5 it would do wonders for your NV intensifier, help with the gain setting) would also look good on it. Let me know how the alignment works out, hopefully no need to use a pole master???

6 minutes ago, niallk said:

I normally throw the scope out with the fan on for a good 2-3 hrs beforehand if I want to observe planets.

Be quiet, since APO’s are ready to go immediately observers who have busy lives will buy them. That or some Deep Space products. 

Does make be wonder if I bought a C9.25 or Mewlon in 2022 when they are back in stock ( No jokes really) how much I would use it.

2 minutes ago, PeterW said:

Yes, the ES corrector doesn’t “add 15%) to your focal length. You want to keep your speed:

Peter

This will decrease the exit pupil, so apart from not standing on tippy-toes what advantage does this give?

An F4 would be maybe better, and have a smoother mirror?

2 hours ago, PeterW said:

What fer seeing faint stuff… designed fer the E-bomb (E21). https://www.bbastrodesigns.com/HET.html

Why I’ve got an f3 mirror waiting for a scope to appear around it.

Peter

Presume a Paracorr is mandatory using such a fast scope?

Also some reviewer who went through lots and lots of scopes in the states rates them

https://www.cloudynights.com/topic/100005-4-apochromatic-hyper-shootout/?p=2381946

5 minutes ago, Piero said:

 

My mirror is 1.5" thick. I start the fan at the highest speed when the telescope is still inside. So, I "wheel" it out, then go back inside to get better dressed, then go back outside with eyepiece case, collimate it, and start observing. At this point I reduce the speed of the fan by half - the views are already acceptable (that's about 1/2 h fan on). Within another half an hour I might switch it off or just leave it at low speed, depending on how the night temperature goes.

 

 

 

P.S.

grip material on wheelbarrow handles is now yellow (black looks cool, but invisible at night time). Wood blocks for making that step ramp were a very temporary solution. I now use the following:

 

Next step is to make a good adjustable chair to be used with both the refractor and the dobson.

Amazing home build!!!! 😀 How high is the eye piece off the ground, do you need to use a step to use it?
It's the one thing thing that puts me off Dobs.

15 hours ago, DesertSky said:

I have read controversial posts about the quality of LZOS glass. Some say they are overrated because they are technically equivalent to FPL51 but not FPL53 or FCD100. Any comments about that?    

OK-1 and OK-4 are more akin to Takahashi Fluorite lens then FPL series of glass. I think Daniel Mounsey did a shoot out of all 4" APO's in a rolling review on CN, and in the end it came down to the TSA-102 and the LZOS. Unless you have all the scopes (Daniels review stretched into 30-40+ scopes, some the same model) you can to review an objective rating is hard to make. 

11 hours ago, jetstream said:

Heres one of the OP's questions- and I dont think there can be much debate over what it takes to see galaxies and DSO- its aperture. Or we can tell the member to drive to very dark skies with his 100mm, or better yet drive to very dark skies with a 10"-12" dob.

You forgot contrast, which also means smooth mirrors or something else without an obstruction .. 😀

On balance a really smooth reflector is best value approach to finding and observing DSO.

Carbon for me, the nudge test result would be very similar, why carry an extra 5 kg with the wood?

But the wood does look better. 😃

Going back again I would of been tempted by AJX over SXP2, the extra capacity opens up what scopes you can mount.

@JeremyS The mount is flexiable, you can attach whatever saddle you want by hex screws, similar to Takahashi mounts. Gives great flexiability. Your favourite Takahashi dealer in Osaka sells Takahashi scopes with Vixen mounts by default!

Interested in how the carbon tripod works out, I’m tempted to buy one, however last year it’s been what has the postman bought today. 😃
 

Not shown but I have the half pillar extension, very much worth purchasing.

On 12/05/2021 at 17:59, Stardaze said:

The problem is whether your collection is likely to change much. The bag works on that score but probably not best if you want a massive collection in one place. Bought a little nanuk case but have outgrown it a bit too quickly. Maybe one day I could see a small bino set in it..

This bag has more flexibility, you can buy another divider bag. See

https://www.vanguardworld.co.uk/products/divider-bag-46

These are quite good to use on its own. So have hard shell for when you go to a dark site and expand by buying a divider bag. For the capacity best value I can find.

42 minutes ago, chrispj said:

It's around 20.8 according to lightpollutionmap.info. If I pop up to the common behind the town I could apparently get to around 21.2.

You don't really have any issues with light pollution, relative to a lot of observers.

From an aperture perspective you can choose what you would like I feel.

While I was looking at some thing else, this came up. Since we are discussing aperture, contrast and reflectivity thought I put it in to the mix:

Why Zambuto?

21 hours ago, chrispj said:

 It's reasonably dark where I am 

Do you know the SQM where you observe? Some people think 21.8 SQM is dark and 21 SQM is dark'ish, while other count themselves luck with a sky around 20 SQM.

On 01/05/2021 at 06:15, Deadlake said:

It would connect to a 2” nose telescope side to a T2 diagonal side in theory. I’ll let you know. 

The above had turned up and works perfectly. Now can swap the UFC between a T2 or 2" without having to pull the nose out. 

7 minutes ago, Mr Spock said:

I just went through the same choice process. I have a 250mm Goto Dob on order

It doesn't matter how good a refractor is, or what some claim they can see, as has already been said, ye canna change the laws of physics.

I used to have a 250mm Newt on an EQ6 before it came too unwieldy. I switched to a C9.25 which was a drop in contrast and quality.

The C9.25 also too a long time to cool down despite being stored in a cool porch. The new Dob is going in a shed so should cool really quick when put outside.

Thanks thats confirmed my thoughts, the C9.25 is off the list. Open or no tube it is. 

Does anyone know how for a reflector to account for reflectance the mirror versus aperture, e.g.

• EdgeHD has around 82% reflectance
• GSO 10" F12 around 96% reflectance

Edit: should of googled.

https://www.cloudynights.com/articles/cat/articles/optical-theory/aperture-comparision-r1901

Just now, dweller25 said:

With a rear mounted fan a 10” Newt will cool significantly faster than a C9.25 and is significantly cheaper too

But not as fast at the GSO. I take the point for example those TS Boren power newts are very attractive, however for using on a GEM the focuser is located at the wrong place on the scope.

Apart from weight I think the GSO 10" has it.

How long does a 10" reflector take to cool down?

I was thinking along the lines of a C9.25 or a GS0 10 F12 Cassegrain which I can put on a goto mount.

Ps: For deep sky aperture is indeed the limiting factor, for anything planets and doubles use a refractor.

2 minutes ago, Stardaze said:

The problem is whether your collection is likely to change much. The bag works on that score but probably not best if you want a massive collection in one place. Bought a little nanuk case but have outgrown it a bit too quickly. Maybe one day I could see a small bino set in it..

I have around 12 normal sized EP's and 4 monster XWA sized ones. The other items would be a two 12.5 mm EP's and a binoviewer. I think I'm pretty covered.
I also have a filter case.
In one place is the idea, so I imagine one row will be take up with XWA's, and then two normal sized EP's per slot. Leaving space.

3 minutes ago, Stardaze said:

I’m going to go with a camera bag this time like @faulksyposted, having similar EP’s. But, I’m probably going to keep mine to a set of 6. The Max case seems to be the best value for money option. 

The other option, a lot cheaper elsewhere is this:

https://www.vanguardworld.co.uk/products/supreme-46d

I like the way the divider comes out, and is then a soft bag. Interesting design.

The puck foam can disintegrate with time and is not space efficent.