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Anyone used the Optolong 2" LRGB filters for using with a mono camera? Thought as their L series filters are so good that the LRGB set would not have any issues, they're one of the cheapest set also.
There's the Baader ones but I've read about the halos they create, the newer CCD ones released this year also seem to have the same issues.
Looking for recommendations.
By Tiago Ferreira
This video is to help you decide if you are a coma corrector buyer and also to help people that struggle putting things to work with the Baader MPCC. I use a 12" f/5 GSO dobsonian reflector newtonian telescope, different eyepieces and ZWO ASI224 and ZWO ASI294 cameras with spacers and a low profile TS extension as my set up which works like a charm with this CC.
I recently bought an Askar FRA400 f/5.6 Quintuplet APO Astrograph. I couldn’t find much info about it in advance – the best was a thread on Cloudy Nights – so thought it might be useful to other folks to jot down some of my feedback. I’m happy to answer any specific questions or clarify any points written in this review.
This is a great telescope that’s fun and easy to use, but with a few issues potential buyers should be aware of.
I got into astroimaging a few years ago, using a Sky-Watcher Evostar 80ED DS-Pro and ASI1600 mono camera plus filters. I enjoyed it, but the arrival of a new baby took a lot of my time (and energy!) so I sold everything with the intention of coming back to the hobby a little later. Barely a year on and I was missing astroimaging a lot, so decided to get back into it, but this time trying to create a simpler set up that would get me imaging on a clear night with the minimum of hassle.
I bought a William Optics Zenithstar 73 II APO 2019 with reducer / flattener, but had terrible issues with streaky corner stars due to backfocus problems. I tried a few things with the help of FLO (great customer support, of course) but in the end returned the telescope as it looked like I’d gotten a duff one. Luckily, at this time FLO started stocking Askar FRA400 f/5.6 Quintuplet APO Astrographs. Its Petzval design promised to be free of backfocus issues (assuming no reducer), which given recent experiences was music to my ears. I decided to go for it, and pushed the button.
I’d be coupling it with a ZWO ASI 2600MC-PRO USB 3.0 Cooled Colour Camera. I went OSC to keep things simple. However, I live in Bristol city centre – Bortle 8 light pollution – so added an Optolong L-eXtreme to my basket so I could still do narrowband imaging.
I decided to forego the optional Askar f/3.9 Full Frame Reducer for FRA400/5.6. This was for four reasons. 1) The L-eXtreme isn’t as effective with very fast systems; 2) 400mm is good to frame the targets I’m most interested in; 3); with the reducer I’d need to get the backfocus spot-on, and I’d had enough of that with the WO ZS73; 4) I’d save £269!
Askar FRA400 f/5.6 Quintuplet APO Astrograph
ZWO ASI 2600MC-PRO USB 3.0 Cooled Colour Camera
William Optics 32mm Slide-base Uniguide Scope
ZWO ASI 120MM Mini USB 2.0 Mono Camera
ZWO EAF - Electronic Automatic Focusmotor
ZWO ASiair Pro Wireless Astrophotography Controller
Optolong Dual-Band L-eXtreme Filter (2”)
ZWO 2″ Filter Drawer with M48 / M42 Connections
Primaluce Lab 30mm PLUS Spacers
William Optics DSD 245 Plate
Dew heater straps
Orion Sirius EQ-G mount
Not being a pixel peeper, I’m not qualified to write a detailed analysis of image quality here, but I will post a single sub so people can make up their own minds. I can say though that I’m very happy with the views – both through the eyepiece and via the camera. There are some aberrations (fringing maybe?) around stars at the edges of the frame -- zoomed examples included below.
Issues and solutions
Build quality on the whole is good, a different league to the 80ED, but not quite up there with the WO ZS73. The dew shield is a little loose, and on the cusp of sliding down under its own weight when the telescope is pointing straight up. I solved this by putting a white elastic band on the main tube, just behind the dew shield – a DIY fix but works just fine. The lens cap also feels a bit loose, but hasn’t fallen off. The default focusser is ok, but doesn’t quite have the premium feel of the WO ZS73. I upgraded with a ZWO EAF, which was very easy to install, and works perfectly. I'd consider this a must if you're astroimaging.
The supplied dovetail is quite short, and makes it difficult to achieve balance if using a heavy camera. I solved this with Primaluce Lab 30mm PLUS Spacers and a William Optics DSD 245 Plate. This allows for good balance, plus there’s room for an ASIAIR PRO to be attached at the back.
All my accessories are attached to the left-side of the telescope, making it slightly off-balance. However, there are enough holes in the spacers and tube rings to allow for the dovetail to actually be attached slightly off-centre to the telescope, allowing for it to all be well balanced. You can buy a Finder Plate to open up more options.
The telescope comes with a conical M68 to M48 adapter. Askar say this is threaded for 48mm filters – ideal for my L-eXtreme, or so I thought. I couldn’t really see where there was a thread in the adapter. I e-mailed Askar customer support, and got a reply two days later saying that the thread is inside the adapter. Fair enough, there is a thread in there, but no way of actually getting a filter inside and screwing it tight. It’s really odd. I e-mailed Askar again to ask for clarification, but this time didn’t get a reply. So, I don’t rate their customer service. From more research online, it looks as if some of the adapters come in two parts that screw together, presumably to give access to the thread. In the end I bought a ZWO 2″ Filter Drawer with M48 / M42 Connections. This fixed the issue, and is very convenient, but is an extra cost that should be considered.
The ASKAR FRA400 doesn’t come with a carry case, which is a bit of a shame.
I’m really happy with my ASKAR FRA400, and think it’ll serve me well for years to come. Once the initial issues were overcome, I’ve been finding it a lot of fun. It’s compact and light -- I can carry the OTA with all attached accessories in one hand. It pairs well with the ASI2600 and L-eXtreme. The ASIAIR PRO controls everything very neatly as well. If I see a gap in the clouds, I can set everything up (tripod and mount in the garden, attach telescope, polar align, autofocus, start imaging) in 20 – 25 minutes. I’m looking into a DIY pier in the garden, which should reduce this to 5 – 10 minutes.
Single FITS sub, straight from the camera (with L-eXtreme):
Single 300s sub with L-eXtreme, debayered, stretched, and resized to 50%:
Random star from the centre of the frame:
And the edge of the frame:
8.5 hours of integration time. One of my very first attempts at processing with PixInsight, so definitely not the limit of what the telescope can do, but more an indication of what a beginner can achieve in Bortle 8 skies:
Views of the Askar FRA400 in my garden:
After much research, primarily on this site and The Binocular Sky, I got hold of the above binoculars. I spent ages writing a review specifically for this site of what I found, as a thanks for all the advice I had received. By the power of idiocy I then managed to post it on Cloudy Nights instead (I had both open in my browser). Too much Christmas port I guess
Anyway, too late to take it down as some have already replied and I guess I shouldn't post the same thing on two sites so here is a link to my review on completely the wrong site No offence at all to Cloudy Nights but I wrote it with the Stargazers Lounge audience in mind and it may make less sense on a US site.
Comparison of Pentax SP 50 WP 10x50 and Nikon Action EX 10x50 CF
It seems that I got less active lately in this hobby, mostly due to the pandemic, directly or indirectly.
However, I'm planning to move from where I'm living now in the close future so I started replacing my gear with lighter and better items.
One of the items was the mount. I still have a tuned SkyWatcher AZ-EQ5 and a stock SkyWatcher EQ6-R. I used both quite a lot, I passed with them long time ago 1000h of exposure. And recently I bought an iOptron GEM45.
The AZ-EQ5 is in the lightweight mount class, but performs quite poor for astrophotography. The original RA worm was a crappy one and I sent the mount to DarkFrame for tuning. I received it back the same, I only lost time and money. I then purchased 2 new worms from China via OVL with some help from FLO. The new one (I didn't test both) have a larger PE than the original one, but a smoother one. The p2p PE of the new worm results in a >60" deviation. When pointing close to the NCP, it guides well below <1.0" total RMS. When pointing towards the celestial equator, the performance drops significantly to 1.0"-1.8" RMS. I always need to use short exposures in PHD to guide it smoother.
In total I spent for the AZ-EQ5 perhaps more than 1800 euros with the tuning, the new worms and deliveries. A lot pricier than stock in the end, but it still has 2 big advantages: mine came with a foldable (towards the mount) pier style tripod and it's light, I can carry the mount with the tripod folded in one hand. The mount and the tripod weight less than 15kg. The other advantage is that I can use the second saddle for the second scope. I used this combo more than a couple of times, with short focal length refractors and all went well. A SW 72ED + an ASI1600 + a finder/guider mounted as counterweight as close as possible to the RA axis, perfectly balances a SW Esprit 80 and a Canon 550D.
The EQ6-R is a lot heavier mount. The head itself weights about 17.7kg, it has a handle, but even standalone it seems a lot harder to carry than the AZ-EQ5 assembled on the tripod. The 2" tripod for the EQ6-R weights about 8kg. Definitely I cannot carry both the mount and the tripod in a single trip for a longer distance. The performance and weight capacity are decent though. Mine has quite a large backlash on both axis, I cannot feel it at hand, but it's obvious when slewing at slow speed. It doesn't bother me for imaging, anyway, since I balance the mount a little east heavy. At most I put a single 200/1200 newtonian and camera on it or a dual setup consisting of a 150/750 newtonian and + a 102/714 refractor and camera, one on top of the other. Weight was not an issue, but a larger momentum + wind affected the guiding performance a little. Towards the NCP it guided excellent at 0.4"-0.6" RMS, but closer to the celestial equator, the performance varied and dropped for this mount too. On Orion, at times the guiding stayed below 1.0" total RMS, but many times it went worse than 1" total RMS. I believe that I never put a scope on this mount and looked through it, I only used it for AP. One thing that bothered me for a while was that the mount was stalling at times due to insufficient power. None of my domestic 12V power sources that I used for the AZ-EQ5 was good enough so I used a 15V 8A source to power the mount. I recall paying around 1300-1400 euros for the mount about 2 years ago.
I used the SynScan app on Windows to drive the SkyWatcher mounts. The app mimics the functionality of the hand remote. The AZ-EQ5 doesn't have a polar scope and I believe I never used precisely the polar scope on the EQ6-R either. The app allows you to perform a 2/3 star align, then it figures out the polar error and you can then perform a polar alignment routine aided by the software. You can select a star for polar alignment, slew to it automatically after select, align in center, then the mount moves a little and the software tells you to adjust the altitude and bring the star in center, then it moves again and tells you to adjust the azimuth and bring the star in center. Simple as that. If you're way off initially with the polar alignment, you might need to realign once or twice again. The SynScan app + drivers are also much simpler than the EQASOM and can be used for controlling the mount from other programs via ASCOM or for pulse guiding.
Now, to the more recently acquired mount, the iOptron GEM45. I spent a lot of time researching what mount would suit my needs. Lightweight, good performance and not astronomically expensive. After many reviews read for the CEM40, I decided to go for the GEM45 as both share the same components. I only saw CEM60's and the older 45 eq. All my astrofriends' CEM60's perform better and more consistent than my EQ6-R.
The GEM45 is supposed to have a PE resulting in an error less than 14" p2p. The graph for mine says that it's less than 10".
The first thing that I noticed when I received the mount it was how small the box it came in was. The mount head is light at about 7kg and the tripod 5-7kg. The second thing that I noticed was what a poor design was made for mounting the mount's head on the tripod. It is unbelievably stupid compared to the SkyWatcher mounts and it's horribly difficult to mount and tighten the mount on the tripod in dark and cold.
Again, comparing to the SkyWatcher, a minus is that you always need to disengage very carefully the gear switches and never leave them engaged. The mount does not have a friction clutch as the SkyWatcher has and hitting or pushing hard the components can lead to damaging the gears. So the mount seems very sensible to handling, it requires a lot of care and mounting the telescope(s) on the mount while holding the CW rod with the other hand can be quite damn hard sometimes. However, there is no backlash.
After setting all the hardware, the next thing was to connect the remote control + the software. It was clear the day I received the mount. It arrived at 5PM and at 8PM I was out of the city with all the software installed.
The iPolar was easy to use, however, you need to connect a separate USB cable for this, the mount does not have a USB hub.
You can perform a star align from the hand controller, but not from the Commander app. You can perform a polar iterate align from the hand controller, but not from the Commander.
Speaking of star alignment, if you choose a 2 or 3 star alignment procedure, I was used to the fact that the first star can be way off when initiating the alignment. The SkyWatcher mounts' software (hand controller or PC app) took into account the error and corrected it for the next stars. iOptron's software (hand controller only, the PC Commander can't align at all) does not. So you need to search again for the second (and third) star to bring it into the view and center it. Only then the model is taken into account. Moreover, the polar iterate align is a pain and, surprise, the polar iterate align and a retry of star alignment after polar adjustment does not take into account the model it computed at the previous star alignment so all the stars are way off if the zero position is not set very accurate. Searching automatically for zero position seems rather a poor joke. So, after being used to the SkyWatcher software, the iOptron seems soooo limited and counterintuitive.
Due to this, I had quickly to learn to drift align with PHD when Polaris isn't visible (it my the case at home on the terrace).
Leaving all the poor engineering and software designs, things are getting better. The mount looks very nice and rotates around both axes very very smooth. You can also pull cables through the RA and DEC axis and have them available at the DEC saddle. There's only a USB 2.0 connector on the saddle, that was rather useless for me so I needed to pull a USB 3.0 cable. However, the 12V power available on the saddle is very welcomed to power the cameras' coolers.
As I type, I'm imaging with 2 ~70mm refractors one on top of the other + 2 mono ASI cameras. Both scopes weight about 10kg. Guiding performance is always below 1.0" total RMS, ranging between 0.4" and 0.8" total RMS, regardless of the pointing position on the sky. If I manage to convince either the mount or PHD to compensate for the PE, I believe it should perform much better as the error increases to >0.6" only when the guiding switches from East to West or viceversa. Plus, being backlash free, it responses very fast to dithering commands and settles quick and, with the small refractors, it didn't seem bothered almost at all by a mild wind.
In the end, I'm very happy with the consistent very good performance of the mount, but still disappointed by the mount attachment to the tripod and the poor designed software and alignment procedures.
I'll come back with more reviews for cameras and telescopes that I own or owned. And images, after I manage to process them. I've more than 100h of data waiting in the queue to be processed.
Clear skies and stay safe!