TS-Photon 6" f4 Advanced

Review

(January 2022)

Introduction

In October 2021 I returned my TS61-EDPH-II to Telescope Service for 'repair' so to speak. Well it appeared it was suffering from chromatic aberration as you can read from my review from it. It appears that telescope needs a new lens assembly, but the telescope and lenses are only due to arrive in March 2022. That's when I decided to in the meantime go back to where it all started and try out a Newtonian telescope from the Photon series from Telescope Service. I opted for the f4 version, because I would like to gather as much as light possible in the least amount of time and the focal length of 600 mm for the 150 mm aperture one was a good match for my current cameras. I'm planning to use and test both the ZWO ASI1600MM-cool and the QHY168C on this scope.

I'm not gone just sum up all the specs and technical data from the vendors website. This review isn't intended to make a fully detailed and technical analyses, but more to share my personal opinion and experience while using it.

Disclaimer: I had good communication with the customer service of TS and they were so kind to offer me a 10 % discount on the telescope. This discount is not related to this review and I can completely freely write without any bias.

Unboxing

Packaging and Delivery

I ordered telescope with some extra accessories on Friday 14.01.2022 and four days later (with a weekend in between) it arrived. So delivery time is pretty fast, but I knew the items where in stock as it was mentioned on their website. The package was well labeled FRAGILE, that's a good thing. Also inside the telescope was well packed with styrofoam.

Unfortunately I noted that there was some blisters on the black paint of the tube. Sure, this will not degrade performance but it's an cosmetic drawback. I immediately contacted TS for a solution, they offered an extra 10% discount which is a nice gesture, although I would have preferred that there was no damage on the tube at all.

Return to sender

After initial testing the telescope, I finally opted to return it to TS and use my 14 days withdrawal right. If you buy a new telescope, you would at least expect it to be flawless without any defects. Unfortunately my OTA passed somehow the quality control, maybe they do only spot checks. So I contacted again customer service at Telescope Service and they will ship a new telescope as soon as they receive the return package. It took about 2 weeks to have a new one delivered at my door. Good service from Telescope Service.

Specifications

Build Quality

Overall

At first sight this telescopes with it's metal tube looks like a solid OTA. The red accessories like tube rings, front and end rings are really cool looking. On the TS website this scope is presented with a classic black vixen style dovetail. So to my surprise I found a very nice fitting red GP level dovetail was included instead.

The mirror-cell is an open design. This will help de cooling of the mirror when outside. On the other hand there's a small gap between the mirror cell and the tube and so there's a real possibility of stray light and dust entering the telescope. Both things you're trying to avoid of course.

Focuser

The focuser is a precise 2" MONORAIL focuser for more stability than with conventional Crayford focusers according the TS website. It accepts 2" and 1.25" accessories. I can confirm that it is a solid focuser especially for the price range. Manual focus is very smooth and accurate. There seems to be no tilt or play in the mechanism.

Accessories

The telescope comes with all the accessories you need to start visual observing. There's a very nice TS 8x50mm strait through finder scope with cross hair and a 35mm 2" extension tube to get into focus with your eyepieces. With my Baader Zoom (6-24mm) Eyepiece it worked well.

Solid spider and big secondary mirror cell. The secondary mirror as positioned well about 1/3 inside the tube, hopefully making it less vulnerable for dew. The spider vanes are not to big and should give nice spikes.

Collimation screws and laser-dot (after collimation). The smaller slotted screw is the locking screw and the slightly bigger one is the collimation screw. I had to find out trail and error, not mentioned anywhere.

Setting up

Balancing

With slightly longer GP level dovetail (instead of the classic Vixen style one), balancing the telescope is more easy. With only an eyepiece connected balancing is no issue. When I connect my full imaging-train on the other hand, I need to clamp the dovetail as far forward as possible (so the weight of the mirror moves backward), and still the telescopes tends to drop a little bit, like nose-heavy.

Collimation

Collimation is actually not my favorite task, but there's no way around when you're using a Newtonian telescope. That's one of the reasons why I started using refractors only a few years ago. But like they say, your first love you never forget. I do like Newtonian telescopes because they give a big aperture for relatively low price and I also like the typical spikes they produce. Anyway, with a little heart I inserted my laser collimator and saw that the mirrors had handled the transport very well. It was only a few millimeters off.

Wega mounting kit for ZWO EAF motor focus on Monorail N2 focuser.

Installing EAF

I bought an extra accessory from TS to mount my ZWO EAF on the monorail focuser. You need to remove the four screws with an allen key and attach the wega mounting kit to it with the supplied screws. Tighten it well as you do not want play but be careful not to over tighten as the wega kit is made from a 3D print plastic. The mouting kit is precisely printed to just fit. From there it is self explanatory if you already worked with the ZWO EAF before.

Disassembling the Wega mouting kit

I was able to return to OTA to Telescope Service because of the blistering paint on the tube. I initially decided to keep it, but at last moment I decided to return it and have it replaced by a new one (see Return to Sender). While disassembling the Wega mouting kit, it snapped into two pieces. It looks a bit like this is unfortunately a design flaw of the Wega mouting kit as the fracture was exactly at a weak spot where the holes are to mount it on the focuser, this spot is very thin in respect to the entire part. Obviously this needs to be replaced as well or an alternative solution needs to be found.

Replacement Wega mounting kit

Having returned the broken Wega mounting kit in the first place, I got a replacement Wega mounting kit as well. It seemed that this one was made of a different kind of plastic and surely felt more solid (heavier), it also had a light shiny finish instead of the mat finish of the first model. When mounting this new kit it also had a better fit, so no issues there anymore as well.


Installing Primary Mirror Baffle

It's been said that the primary mirror edge and clips give a lot of smaller diffraction artifacts and halos on bright stars, as mentioned on Cloudy Nights forum. I noticed this right way when I took my first test picture of M45. Besides the main spikes, that I want of course, you have clearly a lot of smaller spikes and a halo. To remedy this issue, you can install a baffle that, hides the mirror clips and the edges. So that was my plan for this 'little' upgrade. Unfortunately this modification turned out to be easy. I'm gonna try to elaborate.

PROBLEM 1 - Removing the Mirror Cell

If you look closely at the back, you see the mirror cell being held in place with a nut on the inside and a screw on the outside. My first reaction was, sh*t! How the hell am I gonna put this back together once I've unscrewed it. I really went trough a entire thinking process (overnight) on how to 'fix' this.

Eventually I had to be creative and I used a magnet taped on a wooden slat to avoid the nut to fall down and retrieve the nut from out of the tube. This way I was able to unscrew all three screws and remove the cell.

Installing the Baffle

I bought the Wega Telescopes primary mirror baffle for 6" UNC and TS Photon Newtonian telescopes at TS . To install the baffle you need to unscrew the three retaining clips, completely or loosely as you want. The baffle has a conical inside and a flat side. I put the flat side on the mirror so I didn't have any slit (gap) between mirror and baffle. I fastened the retaining clips again, with just enough force to keep everything in place. Some recommend to be able to stick a piece of paper between clip and mirror to avoid pinched optics, but I assume that the pressure is now more equally divided around the mirror because of the baffle. So I have to wait for the star tests later.


PROBLEM 2: Re-installing the Mirror Cell

Now came the greatest challenge! With the secondary mirror in place it was impossible to reach the back of the tube with my arm to be able to retain the nut while screwing the cell back into place. The only way to do this is to remove the secondary mirror as well. Initially I tried a wrench, but it was too thick to be able to fit between mirror and tube to keep the nut into place while screwing. So than I made use of the thin wooden slat I had before (with the magnet) and drilled a hole in the other end. Just a little smaller than the size of the nut to be able to get a good grip on it. Now I was able to keep the nut into place while screwing the cell back on. Whew, I finally managed it.

WARNING !! MAJOR DESIGN CONCERN !!

I must warn you all when buying this telescope. Of course it's a great scope but the unfortunate design of the mirror cell and how it is mounted onto the tube is really an issue! There should have been more thought into this. It's also a major concern when you want to regularly clean the mirror, removing the cell is not a task that you can do in a few minutes, let alone to put it back. If I would have to mention one flaw for the telescope than it's definitely the design of the mirror cell together with the collimation screws that are not easy identifiable and rather small.

Secondary mirror removed.

Wrench is too thick to access the mirror cell inside.

Custom-made tool for holding the nut into place.


First Light Visual

So lucky to be able to test the scope at it's first day! A few hours after delivery I had it already outside to the my classic "church tower test". Our church tower in the village is ideally located from my backyard, so I can use it to align my red-dot finder or the finderscope and take a look at the clock or weathercock. I needed the 35mm extension tube to be able to focus my Baader Zoom eyepiece and the focuser needed to be out almost at the most extended position. This looks rather impressive.

The telescope setup weighs between 5,5 and 6,5 kg depending on the eyepiece (camera) and finder (guidescope) you use. The mount I'm using for this scope is an Celestron AVX Advanced Mount and this is a perfect match for this telescope.

I took a few test shots through the eyepiece and both visually as on the photos I don't see any noticeable aberration or deformations. For daytime observation though depending on the magnification you can see the black obstruction from the secondary mirror.

Stars without coma-corrector

In the center field of view the stars are quite sharp and round, but with this fast-system once you're looking to the edges of your eyepiece the stars start to show clear signs of coma. I don't have the adapter for the Baader MPCC Mark III corrector to use it visually with eyepiece, so I can't tell what that would do. I only bought the photographic coma corrector as that's my main goal anyway. But an adapter exist to use it with your eyepieces.

First Light Photographic

Baader MPCC Mark III and Coma

My initial intention was to buy the TS PGU Superflat Corrector as recommended on their website. But after some email exchange they recommended this Baader MPCC (Multi Purpose Coma Corrector) as it was a much shorter design and so it would not protrude in the focuser too much, causing really too much vignetting. Quote: "I only would change the GPU with the MPCC , because with a 6" Newtonian the GPU will vignette a lot, really a lot (it will protrude inside the tube). " unquote.

The coma corrector has also two different backfocus distances depending if you use the T-2 or M48 thread. I had to use the Stop-Ring as an additional spacer for my setup because I didn't have anything else readily available. Luckily this Stop-Ring was about 2 mm itself, so I come very close the the required backfocus. I presume that a separate expanding ring can be ordered according Baader itself.

Baader MPCC Coma Corrector

Baader Expanding Ring T-2f / M48m (T-2 part #29)

Flats

Flats will definitely needed to be taken with this 'fast' system as there's still quite some vignetting visible. In the first test picture below from M45 (the Pleiades) you can clearly see the vignetting. This picture is a stack of 37x60" exposures with CLS filter, during a full moon night, so not the best for now. They are still some issues to solve, namely collimation and focusing should be better.

Coma inspection with PixInsight. In the upper right corner there's still some dis-formation, moist likely this is caused by the mirror clips to fastened, pinched optics distortion. For the other corners at least the coma error looks quite acceptable.

37x60" with CLS filter, ASI1600MM-cool.

Battle False Light

First of all because of the open mirror design, lots of light can enter the telescope via the back through the mirror and the casing. This stray light can cause lots of reflections and issues in the frames. To avoid this I did a low-cost-upgrade of the system. To cover the back cell I used a 3 € black latex swimming cap. To avoid light reflecting in the front of the tube I cut a 3.5 € yoga mat into the right size.

M45 - Pleiades

On the night of February 28th 2022, I was able to catch about 1,6 hrs of data on M45. I switched to the QHY168C camera instead of the ASI1600MM-C, because I wanted to test the APS-C sensor size and see how the Baader coma corrector performs. It looks like it's performing quite well. The deformation I see is more from pinched optics I think. I took 60 seconds and 120 seconds subframes and stacked them all together in AstroPixelProcessor, together with the required darks and flats. The spikes look really fine and straight and for data, I see lots of detail in the dust clouds. Overall, happy with the result, but still the pinched stars need to be corrected, for that I need to remove the lens cell again, and I'm not looking forward to do that.

Moon

At the end of the first night and some test shots at M45, I pointed the telescope to the full moon. Below is a stack of 25% of the best frames of 300 .AVI file with AutoStakkert and some fine tuning in Affinity Photo. It was taken with the red filter and the ASI1600MM-Cool camera.

Conclusion

I've not been able to fully test this telescope yet, but just from the initial impressions it's a very nice scope for the money.

Image quality is both visual (tested during daylight) and photographic very good. On top of that it's a good looking telescope with the red accessories. Decent enough build quality in a compact volume and not too heavy, so easy for smaller mounts and transportation.

Balancing might be a little issue depending on the accessories you put on it. The collimation screws on the mirror cell look a bit cheap and are very confusing, what is locking screw and what is the adjustment screw. It would be nice if those where replaced by the nice big turning knobs, bob's knobs (or like the bigger models). One major downside is the design of the primary mirror-cell. The way it is mounted on the tube, with nut and screws, makes it an exhausting task to remove it and re-install it for example when you want to clean the mirror. The collimation all-in-all of this scope was rather straight forward and until now I only did it with a laser collimator with so far sufficient good result.

I can certainly recommend this telescope if you're looking for a small f4 newton without having to spent thousands of euro's for an f2.8 or f3.2 version. As the faster the f-ratio gets it's also more demanding for collimation, that's also something to consider. Of course you can't expect all top-quality, but again given the price of the scope it's pretty good build quality and usability. Really the major downside for me is the design of the mirror cell and the way you need to remove and install it again.

Another thing is the stray light that can enter the scope easily via the back. You should definitely put some sort of cover over the back to avoid this false light entering the scope.

Anyway, I'm planning to have a lot of fun with it.