Askar 200mm f4 Astrograph mini review

[mldee]

I've always liked fiddling around with widefield astro using old Pentax lenses, but most of the results were a bit underwhelming unless really stopped down.

Anyway, I chanced upon a YouTube video by "Cuiv, the Lazy Geek", about a month ago, featuring an Askar 200mm lens specifically designed for Astro photography. Here's that video:https://tinyl.io/4u06

I made a snap decision to see if they were locally available and purchased one from Testar in Sydney. Only took a week for delivery. So far, no buyer's remorse at all. It's a magnificently constructed lens, 6 elements (3 ED) in three groups. Very smooth coarse and fine focussing rings with screw lock, and 12-blade f4 to f22 diaphragm, although f4 is the sweet spot. I'm no expert at photographic lenses, but I think this would give most similarly priced Canon and Nikon lenses a run for their money.

An M48 threaded interface with a built in M48 filter holder too! M48 to standard M42 adaptors and extenders are easy to come by as well, with standard 55mm back focus required. Here's Cuiv's latest comparison review:https://tinyl.io/4u07

Not cheap, a bit over $1k, but if you want to do widefield, probably the most cost effective solution to good pics. I have mounted mine with an ASI2600 OSC on an old vixen GP + Synscan mount using an AzEq6 tripod I had, sitting on my front south-facing verandah, where I presently get great views of the SMC and LMC at civilised evening hours. The results have been most satisfying. Pic is 30x20s stacked and stretched in ASI Studio, no other processing.

[raymo]

Looks very good; why did you limit subs to 20secs?
raymo

[mldee]

Basically just to see how they came out. The LMC is very bright here, and being a widefield shot, I was slightly concerned about blow out from bright stars. I've since taken another 50 or so shots, but haven't processed them yet. One of the problems with short exposures is the size of the files, 50+ Mb each with the 2600MC.

I also like to go to bed reasonable early :D

[raymo]

If you like to go to bed reasonably early you're pursuing the wrong hobby.:)
raymo

[AdamJL]

Great stuff. ASKAR/Sharpstar make some really excellent quality telescope.

[DaveNZ]

Ive been using the ASKRA Fra400 with their focal reducer.

Very happy!

[AstroApprentice]

Hi Mike,
The Askar 200 looks great. If you’re after a motorised focuser for it, DSD makes a kit for his motor https://deepskydad.com/autofocuser/askar200 and for the ZWO EAF https://deepskydad.com/autofocuser/askar200/eaf

[mldee]

Adam and Dave, sounds like you're also happy with their products. Seems to me that some of the newer astro products out of China are really getting into best-of-class territory.

Jason and Hans, yep, I ran off and ordered the Askar focus kit from AliExpress as soon as I heard about it. Good to see Testar is now also selling it at a very competitive price. Wasn't aware that there was also an alternative product. However the Askar price does seem to be a little more attractive, as both items are basically the same concept.

Mine arrived a couple of days ago and it's one of today's projects to install it. I'll probably post a pic although there's plenty to see on Youtube already.

Hopefully Nina with Autofocus will further improve the generic-quality of my Southern sky widefield happy snaps:P

[JA]

Hi Guys,

One thing to bear in mind with the motorized focusers mentioned is that given their design with the lens foot integrated with the ZWO EAF focuser, is that this significantly increases the height of the lens & foot assembly. As a result the centre of gravity of the assembly moves up higher (further from the base) and more importantly when mounted on a equatorial mount moves further outward from the RA rotational axis and thereby increases the drive torque required to be supplied by the motor, by I would estimate*, just on ~50% in the case of a small portable mount like the AZ-GTI.

That 50% increase in required drive torque may make no difference for a larger mount, but might be a consideration on smaller mounts, where the payload is close to the limit, or where one wants to minimise loading in order to possibly improve tracking accuracy.

It would have been better, in terms of minimising any increase in drive torque for the design to have mounted the ZWO EAF to the side of the lens, or possibly even above it, given the 1.8kg lens mass.

*Estimate based on the following specified, measured and scaled dimensions....
AZ-GTI RA rotational axis to base of Vixen dovetail measured as 60mm
Askar 200mm f4 Vixen dovetail foot base to lens centre line Scaled from drawing as 81mm
ZWO EAF height = 59mm + a few mm for bracket thickness

Best
JA

[AstroApprentice]

Hi Mike,
Did you notice DSD now makes flip flat panels for the Askar as well:
https://shop.deepskydad.com/product/askar-200mm-acl200-flap-panel/

[Wussell]

It is a great lens.
I was surprised by the weight of it, and also noticed that it has been flocked.
Just this minute ordered the focus kit and dovetail from Testar. Just need to get a EAF focuser and the ZWO ASIAIR Pro.

[mldee]

Hi JA,
Thanks for the heads up on CoG movement, etc, the same concern had raised its head with me, especially as I initially had a guide scope and camera perched on top. My Vixen GP mount is approx equiv to a HEQ5.
I am presently mulling over how I will arrange things with the focuser. I could leave the existing vixen foot in place and replace the upper handle with the new focuser setup, that would keep most of the mass lower down, but not sure if it can be done. News at 11.

My vixen bar has a transverse plate on it, from an old side by side kit that was trashed, with the Synscan box and a NUC, mounted one to each side. I am thinking of putting the guide scope there as well. Getting a bit crowded, but hey, thrill of the hunt is what it's all about. More news at 11....

Jason, no, thanks for the heads up, will take a look.

Russell, I have been driving the guider EAF (to be moved to the Askar), from the mount NUC via RDP and seems to work OK.

[mldee]

Well, it's 4pm and ready to put it on the mount. Took a few pics for posterity.
By rearranging the vixen bar/transverse accessory plate, I reckon I've only added maybe 30mm to the overall height and have tried to layout the components to centralise the C of G over the centre of the vixen bar. We'll see how it looks when I balance the mount.

The install went very easy.

[LewisM]

I've gone a similar route, but chose the Redcat 51 over the Askar. I couldn't be happier! It is SO portable, VERY VERY sharp, built in tilt adjustment and a Bahtinov integrated in the cap. Happily rides on the EQM-35 GOTO mount also - doesn't even know it's there. Definitely wide and fast enough for me and the ASI533MC (using an l-eXtreme filter too)



Love it. Sold my Taks, enjoying portability and simplicity.

(yes, I swapped the red vixen bar for a silver one - didn't want to mar that lovely Redcat bar :) )

[Pepper]

That’s a neat setup Lewis. I was tossing up between the askar and the redcat to use with my 533.
Definetly be interested in seeing some pics out of that.

[AdamJL]

Loving these shots of these widefield setups!! Keep them coming :)

[mldee]

Just for you... Old Vixen GP Synscan mount with RDP NUC on Skywatcher AzEq6 tripod, Pointed to SCP from front verandah. Great widefield site for Magellanics and MilkyWay, especially in winter, with a nice wood fire just inside the door.

By the way, the autofocus in Nina worked splendidly on first try last night.

[DaveNZ]

FRA400 with Eagle and ASI294mm on a CEM70.

[mldee]

Gotta love that Prima Luce Eagle, makes my DIY transverse plate and NUC setup look positively prehistoric:thumbsup:

My ancient mount and Synscan didn't talk together too well last night, so images were really poor. Here's a quick and dirty poorly stacked and processed in APP/Startools: SMC/ngc261. 30 x 60s

[JohnH]

Just wanted to echo the sentiments on this thread - I made this change to widefiled and am very happy with my setup....shot of ETA with dual band filter from middle of Sydney (Harold Park, Forest Lodge). I have the FR but have not used it yet....

[LewisM]

Just received this morning the Redcat special prism diagonal and the Canon Wide camera flange.

It now covers imaging (CCD/CMOS), visual as well as being VERY suitable as a manual lens for the DSLR.

Looking through it with the diagonal was a joy - VERY flat field, beautiful image and extremely sharp.

Only not so fun thing is balancing it on a stiff mount - not too difficult in Dec (not much moment arm to move anyway), but a real pain in RA as it is SO light. I don't think the mount will care much anyway :)

[LewisM]

Oops, forgot the diagonal image.