TS 61EDP II Review

Introduction

I was looking for a suitable wide field telescope I could use together with my ZWO ASI1600MM-cool camera. Several candidates passed the review. The main criteria where :

• Portability to be able to take it in the field mainly for visual. 

• Usable for both visual and astrophotography. 

• Flatfield on the image sensor. 

• Acceptable image scale  with my ASI1600MM-cool. 

In the table below I made a comparison of the different scopes with their focal range, price and image scale in combination with different cameras (prices are from March 2021). The line in blue are the specs of the setup I'm already using. I've put it in the table to be able to compare of course. 

The TS CF-APO 70 was also a worthy candidate, because I could use my reducer/flattener I already owned. In combination it gave also a 3° field of view. But finally I decided to go for the TS 61EDPH II because it gave a slightly bigger field of view and the supplied reducer/flattener was especially tailored to work with this scope. 

Unboxing

I had a long email conversation with Telescope Service in Germany before finally ordering the package. At a certain moment they already placed to order for me, because it was the second to last scope they had in stock. Next deliveries where due for June/July, so 3 month later. It was send with UPS on a Friday and the next Tuesday it was delivered at my pick-up-point of choice. Opening the parcel is always a special moment, feels like childhood days unraveling the bow from your gift. 

TS-Optics 61EDPH II 6-Element FPL53 Flatfield-Apochromat

From the seller: "The TS-Optics 61EDPH is designed for astrophotographers and nature photographers. It convinces with its compact dimensions and its high-quality 3-element FPL53 lens (glass from Ohara - Japan). The 3-element corrector has been specially developed for this APO and produces a corrected image field with 44 mm diameter and without chromatic aberration, ideal for full-frame cameras. The fast aperture ratio of f/4.5 allows short exposure times. The 61EDPH is a fast and portable travel scope for astrophotography. " 

I couldn't actually make a better summery for where this scope is for. It's exactly the reason why I bought it.  

Build Quality

Immediately obvious is the fine build quality of this telescope. Nice aluminum tube with white mat coating on the outside with red glossy highlights. The inside of the optical tube is like black mat paint with several very fine baffles the entire length. It all feels very robust and smooth at the same time. 

The retractable dew shield tends to slip a bit when pointing at the zenit and I see no way to tighten it more to lock it in place. The red aluminum tube cover sits also a bit loose and falls of when pointing down. I quickly prevented this from happening again by installing a second thin strip of black felt.  

There's no locking screw* for the focuser to lock it into place, but it has an "Load Adjusting Screw" instead, it controls the tension of the focuser. I've noticed that the focuser can easily hold focus with my image train (camera and filter wheel) or a DSLR attached to it. 

The nicely finished and CNC constructed tube ring gives the scope a touch of red fashion. But again a minor point of critique, when the tube ring is  screwed closed, the scope can still move inside the ring, meaning the ring doesn't clamp the scope like it should. Again I needed to add two small strips of black felt to the inside of the ring to reduce the play and have the tube ring really lock the scope. 

The carrying handle is a nice feature to install for example a guide scope or other accessories. But it's not a convenient way the really carry your scope because the balance point (when camera attached etc. ) is way off so you have to twist your hand to keep it balanced. 

First Light

As it is very unusual to be able to test your new equipment the same day, I was lucky! The next three nights where forecast to be clear. So I got to 'work' immediately. I mounted the scope on my Celestron AVX mount during the day. I wanted to test it with my old Canon 450D DSLR to use it as a telephoto lens. As I was doing this in my backyard, I only could take a few pictures of the church tower, a W.O.I remembrance statue and some blossoms. I played a bit with ISO and shutter speed. 

The first two images were taken outside in my backyard and without the reducer attached so at a focal length op 336 mm. The last two with the reducer/flattener attached to the scope making it a 274 mm focal length and  were taken from inside thru double panned window. These images are the raw image from the camera, no editing done to it. 

The Reducer/Flattener

The reducer is a sturdy constructed 3-element APO lens. You can attach 2 inch filters to it, but than you have to first unscrew the reducer into two pieces. Than you can very carefully screw a 2 inch filter inside the reducer and put the two pieces back together. I have no 2 inch filters, but I imagine this will definitely take some practice to do this without putting dirty fingers on your filter.  

The back-focus required when using the reducer is 55 mm. In my case where I use a ASI1600MM-C camera and EFW, I need an additional spacing. I calculated this by subtracting  the 20 mm of the EFW and 6,5 mm of the camera from the 55 mm. So, 55-20-6,5 = 26,5 mm. I've solved this by using two adapters and some spacer rings. The 55 mm correct back-focus is quite critical for a correct illumination of the focal plane and thus round stars into the edges.

Nature Observation

This telescope also suits well for nature observation or bird watching. The dovetail also has a 1/4" photo thread, so this APO fits, like a telephoto lens or DSLR, directly on every photo tripod. Together with my Baader Hyperion zoom eyepiece from 8 to 24 mm this gives a magnification range of 14x to 42x with very fine contrast and detail. So this scope is ideal as a grab and go for nature/daylight observing.  Below also a small movie of a tomtit, this was filmed with my mobile through the eyepiece at 14x magnification. 

Bigger sensor test

Some widefield targets I took with this telescope can be found below. It's together with the QHY168C with APS-C sensor. I'm quite impressed about the star forms being almost perfect up into the corners. Sensor details: 4952x3288 pixels and 4.8 um pixel size. 

Chromatic Aberration

I was using this telescope for about 6 months when I got the chance of buying a dedicated one-shot-color camera, the QHY168C. Of course I was eager to try this OSC out together with this wide-field wonder. At first glance it gave a wonderful result. Have a look at these images: M31 - Andromeda Galaxy , NGC 7023 - Iris Nebula , Heart and Soul Nebula . 

Then I saw a video from Cuiv The Lazy Geek, explaining the potential problem with chromatic aberration in the Sharpstar 61 series. TS61 is basically the same telescope but other branding, so I did a closer investigation of my own pictures. Unfortunately I found out that my TS61 suffers indeed from this chromatic sickness. To be honest I was already wondering why I had all those blue halos around my bright stars, but this video made it all clear for me. I started to investigate further...

Further testing for chromatic aberration I did with my mono camera, the ASI1600MM-cool. So I compared the 3 filters RGB. Obviously the Blue filter gave very blown-out stars with halos, so the conclusion for me was obvious, my TS61 suffers from "Chromatic Sickness". 

Return to Seller

After having coped with the shock of the diagnoses, I immediately contacted Telescope Service  in October 2021, my telescope had still warranty. They offered immediately to help to find out the problem and troubleshoot. That's why I took some of the test-images from above. Eventually the proposed to have it shipped back to them. They are going to replace the front lens-element or give me an entire new one. Both is fine for me. In the meantime of writing (December 2021). 

Got new Lens Cel

After more than 6 months due to the know delivery issues at that time (Covid-19) I finally got my telescope back from TS. They installed a new front lens cel and put it on the test bench. Customer service from TS assured me that I now would have a very good optical assemble performing very well with no to very little CA. Of course it took some time to put it the test due to lack of free time at the right (weather-wise) moment.  Below you see an image of Messier 45, the Pleiades, an remarkable result in my opinion. There's an obvious improvement in respect to the previous lens cel version. 

Conclusion

TS-Optics has made a very affordable wide field telescope. Fulfilling my criteria, portability, weight, multi-discipline use. It has a very nice finish and it is definitely a well constructed telescope. Whether you are looking for a small refractor to do nature observation or for a small wide field APO for astrophotography, I can recommend this scope.  Given the small points of criticism, like the tube ring and dew cap issue, which were easily solved, it's a fine instrument. The reducer is a very nice instrument, only a little unfortunate that the attachment of a 2 inch filter inside takes a bit of fiddling. I'm very looking forward to put this scope to the ultimate test in Autumn when the most wide field targets present themselves in our Northern hemisphere. 

Finally after I got a new lens cel from TS and I was able to test the TS61 further I was really blown away. I'm really happy that TS was able  and willing to replace old lens cel. This is a really nice affordable telescope as an cheaper alternative for the high-end trademarks. Now, would I recommend it? Yes, but be sure to have an newer sample or one that has been upgraded with a new lens cel. I'm going to have lot's of fun with this one.