TSAPO100Q vs TSAPO81Q - Dilemma. I need your help

[Qwiati]

Hello to you all,

I am looking to buy my first refractor telescope and having done some research and budget available I narrowed the choice down to two models:

TSOptics Imaging Star 100mm f/5,8 - APO Quadruplet Flat-field Astrograph - aperture 100mm / focal length 580mm

or

TSOptics Imaging Star 80mm f/4.4 APO Triplet Flat-field Astrograph - aperture 80mm / focal length 352mm

My existing imaging scope is SkyWatcher Dob Newtonian - aperture 254mm / focal length 1200mm  f/4.7, cooled with filed flattener and upgraded dual speed focuser on Orion Atlas EQ-G mount

I use un-modded Canon 70D and Astronomik CLS light pollution filter.

Dedicated guided scope is Orion 80mm shorttube guide scope with Orion Starshot  Autoguider camera.

Travel to dark site with the existing setup makes very hard to organise and the only option is to photograph the night sky from my balcony where the sky view is limited and light pollution is high.

I am interested in wilder field, deep sky imaging - galaxies, nebulas and clusters.  Planetary imaging or visual use is not a priority.

As I still need to decide on the new scope I would like to ask anyone with the experience with 80mm and/or 100mm triplet/quadruplet refractors. I am not sure how much would I gain / benefit from buying the 100mm vs 80mm?

Would the fast and short 80mm triplet perform as good as the longer and slower 100mm quadruplet taking into consideration light pollution and type of the camera used?

There is almost 1000 euro price difference between those two TS scopes and I am just not sure if it is worth spending extra on 100Q ??? Or is it? Please help me to decide.

I would greatly appreciate it if you kindly give me some feedback or advice.

Happy Holidays to you all !

Kris  

[ronin]

I would go for the 80mm, cannot see any advantage to the 100mm other then a slightly bigger image.

Cannot think why you want a reducer on the 100mm but it is already there on the 80mm.

As you say for the additional cost of 1000€ which brings the 100mm close to double the 80mm price there does not seem to be anything to make the 100mm worth that extra cost.

[Qwiati]

It would seems like no brainer, but 100mm is a quadruplet and I think also have better optics plus 3inch custom focuser and the whole 20mm more light gathering... but is that worth the extra money?

[Astroscot2]

I would like to see some images taken by the 80mm before purchasing, f4.4 is very fast and id be interested

in how well it controls blue bloat around the brighter stars.

[Qwiati]

Very good question... I wonder if anyone here could share their experience with either of those scopes...

Another option that just popped up is this:

 TS Photoline 107mm f/6.5 Super-Apo - 3" CNC dual speed focuser / modular carbon tube + TS 2.5" PHOTOLINE Field Flattener for recfractor telescopes - for pinpoint stars across the whole field

Would this scope be much better than the 80mm? 

[conspicuity]

Not quite the same: I have a TSAPO80Q (F=520mm). I am a  relative (i.e. absolute, really) newcomer, but, for what it's worth, I have found this scope very satisfactory both visually and in imaging so far.  For me the 80/20 rule applied - i.e. you get 80% of the benefits for 20% of the cost.

If you're a real perfectionist, you will invest more, but the benefits do not accrue in direct proportion and, certainly at my level, 80% was enough.

I also looked at the sizes of the most commonly imaged deep sky objects and found that more than 80% would fit on the sensors I was planning to use with this 'scope. There's a big difference between 352mm and 580mm, so I'd recommend thinking about your likely targets in this way.

I find the most difficult thing in astronomy is the investment choices... good luck with yours!

[Qwiati]

Thanks... doesnt make it any easier

Kris

[Qwiati]

bump

[han59]

I have both the TSAPO65Q  (65mm opening, 420mm focal length) and TSAPO100Q (100 mm, 580mm focal length). They are both tremendous imaging machines. Stars are tiny points both in the middle as in the centre. They are both fast, F/6 or so and very good for making images. The only difference is that with the APO65Q you get a wider field and objects are smaller on the image. Exposure time is about the same for both telescopes

For visual, the opening both of the 65 mm and 100 mm is just not enough for deepsky. For visual you better stick to the 8 inch or buy a 10 inch telescope. I think you will be happy with the TSAPO65Q  (65mm) for only Euro 600,- or so. I bought the APO100Q because I could afford it and some objects are too small. I fact, I also have a  6 inch RC with focal length of 1380 mm for the smaller objects. The only problem with this one is that at F/9  it is too slow and requires long exposure times.

Ideally you will need two telescopes (astrographs) for imaging:

F/6, focal length 400-600 mm

F/6, focal length 1200-2000 mm

The last one gets pretty big, bulky and very expensive.

Have a look to the images available on the web or my page www.hnsky.org/2011plus.htm

I use the QHY8 camera.

Han

[Earl]

One of these might be worth a research im hearing good things about them.

http://www.firstlightoptics.com/william-optics/william-optics-star-71-f49-5-element-refractor.html

[han59]

An other thought about the

TSOptics Imaging Star 80mm f/4.4 APO Triplet Flat-field Astrograph - aperture 80mm / focal length 352mm

Great price and very fast. The focal length is short, very short.  Great for very wide field but due to 352 mm focal length, objects get very small in the image. Very short exposure tiems. Great for M31 but smaller objects like M13 will become tiny on your images. If you buy this thing, I think you will find a need an other telescope with a longer focal length later. Have a look to my APO65Q images with the 420 mm focal length

I'm surpriced they can make these telescopes for that price.  The "Okularauszug" clamping of the TSAPO81Q  looks simpler.

Han

[ollypenrice]

I've used, extensively, the Takahashi quadruplets at 85mm and 106mm. The nice thing about quadruplets over triplets with flatteners is that you do not have to respect any chip distance, you just focus and go. The difference in aperture is neither here nor there and both scopes gave stunning results on deep sky imaging. The difference that does matter is simply focal length. It alters your field of view. You mention imaging galaxies so, apart from M31, neither scope has enough focal length to do galaxies in detail though the bigger one would be far better. Even a metre is short for galaxies. I always think they open up at about 2 metres.

I can't say that I understand the smaller scope. It has a three element corrector in the back and a triplet lens at the front? Is that right? And is the corrector included in the price? And what about getting the right chip distance? Look into all this carefully.

The 100Q in the hands of Ole Alexander (Xplode on here) has done some great work. I'm just a bit suspicious of the F ratio in the smaller TS scope. Getting good colour correction at those F ratios is never going to be easy, but maybe they've managed it. Six elements is rather a lot to control though...

Olly

[Qwiati]

Thank you all for your input and advice.

I ordered the TSAPO81Q. Awaiting delivery today. I will report back my first impressions and hopefully share my first astro pics taken using that scope.

K

[RafalT73]

Thank you all for your input and advice.

I ordered the TSAPO81Q. Awaiting delivery today. I will report back my first impressions and hopefully share my first astro pics taken using that scope.

K

Hello, I am very interested in your experience with TSAPO81Q. Actually I am also going to buy this telescope, so if you can share with your story it would be very helpfull

[Qwiati]

Hi, 

I am sorry for the delay in getting back to you and sorry to disappoint you, but after few sessions with TSAPO81Q I decided to return the scope....

The quality was not there, despite very much effort from TS we were not able to achieve focus without introducing big comma around the edges.

We have tried different spacers and settings, but not luck.

I am not sure if there was something wrong with the example I owned or that would be the case across the product, but returning the product was only option for me.

K

[damnut]

Sorry to hear disappointment with such an expensive piece of kit. At least you were able to return it. Do you have any further thoughts on what you may purchase now.??

[Qwiati]

Already found my perfect scope ;-) William Optics GT102 APO ! wow what a nice piece of kit - on one hand shame my experience with TSAPO81Q was so disappointing, on the other... WO GT102 ended up being the perfect choice...

Support from Telescope-Express on germany was amazing, shame we could not fix the comma issue...

K  

[Earl]

Its a shame it did not work out, I was tempted at one for a while, after i tried the 65 whcih had the usual issues.

[RafalT73]

Hi, 

I am sorry for the delay in getting back to you and sorry to disappoint you, but after few sessions with TSAPO81Q I decided to return the scope....

The quality was not there, despite very much effort from TS we were not able to achieve focus without introducing big comma around the edges.

We have tried different spacers and settings, but not luck.

I am not sure if there was something wrong with the example I owned or that would be the case across the product, but returning the product was only option for me.

K

What a surprise  !!!

I was sure to hear only positive opinion about TSAPO81Q. Very short focal length and quadruplet optics system seems to be a perfect solution for big sensors. OK,  good to know. I will try to find more opinion but yours I will take very seriously. I am curious what did they say in Telescope-Express?

[Qwiati]

Telescope Express was very helpful, they have said that the issue with coma was the distance between focuster and imaging chip, they have send me few spacers and T-rings to try, but one fixed the coma closer to the center of the image, leaving large coma on the edges, the other was fixing only on one side of the image and another did the opposite. After few days of trying different distances and struggling to get no coma corrected, they asked me to send the scope back. Like as mention before, this might have just been problem with that scope, but based on the experience I would not buy this scope again.