Takahashi FSQ-106ED

[jase (Jason)]

Introducing the new Takahashi FSQ-106ED (Flat-Field Super Quadruplet).

Well, having waited six months, the new Takahashi FSQ-106ED has finally arrived (I kid you not – I placed the order back in Nov’06). Overall, I’m impressed with the physical improvements compared the FSQ-106N. The heavy-duty focuser has significantly improved and now supports 5kg payloads such as heavy CCD cameras and the like. There has been some discussion on a shorter draw tube being available to support even heavier payloads. The modified Petzval design remains the same with two of the four elements using ED glass. The major improvement is the colour correction up to 1000nm. The OTA weighs in at 7kg so it’s relatively light. Certainly not a problem for the Losmandy Titan which is rated at a 45kg photographic payload capacity.

I have a new RoboFocus R&P stepper/controller and bracket also waiting to be mounted on the FSQ-106ED when I get a chance. If its anything like the original FSQ, it will be rather temperature sensitive requiring refocusing many times during the night. Hence, the reason for purchasing a temperature compensated focuser such as the RoboFocus. This also allows remote focusing control.

To ensure I don’t experience vignetting and leverage off the giant 88mm image circle this scope delivers, I’ve also purchased the Takahashi Feldstein#6 adapter that screws the STL11k directly onto the 72mm male thread. Thus I don’t need the 2” SBIG nose piece which is prone to cause vignetting.

I have not ordered the Reducer-Q accessory (yet), this drops the native focal length of 530mm down to 385mm @ F/3.6 – nice fast,wide, flat fields that the STL11k will enjoy.

More information on the new FSQ-106ED (with a comparison to the original FSQ-106N) can be found at http://www.optique-unterlinden.net/hp_fsq106ed.htm

Anyway, attached are a few pics. It will be a little while before it sees first light. I will be sure to post an update soon.

[JohnG (John)]

Now that is nice, what more can you say.

Cheers

JohnG

[Ric]

Wow Jase, that's nice I'll bet your a happy chappy.
I looking forward to seeing your images from it.

Cheers

[richardo (Rich)]

Now that's what I call a very very nice scope indeed....
and being a superseding model on from it's predecessor, well, you are going to have a truck load of fun getting some hot images down with your stl11k.
Your fOV is going to be something else...
Made for imaging that's for sure.

Looks like you've done all your home work with getting the right attachments to make things work well....

Congrats...... you'se sure be one happy chappy I'd say!!

Look forward to your first light images.

All the best
Rich

[jase (Jason)]

Thanks JohnG, Ric and Rich. Indeed, it's all starting to come together.

I've done some research on this. The FSQ when operating at F/5 has a CFZ of 55 microns. The RoboFocus has a step size of approx 7.5 microns, so hitting the focus sweet spot shouldn't be too hard. I sense maintaining critical focus is going to be a little more difficult. From reports I've read, the new FSQ is no different to the original when it comes to temperature shifts, so I suspect I will be refocusing a lot. Which isn't a major issue once I establish a good v-curve model in FocusMax. Actually, the Custom Scientific (CS) filter set I have are not all parfocal so refocusing is inevitable - the CS Ha filter is slightly thicker than the CS LRGB set.

Anyway, attached are a few final pics showing the STL Feldstein#6 adapter, Robofocus mounting and the entire imaging train - which is very clean. There are no focal reducers or in-path focusers which would change the focal length. I will do some plate solves to determine my precise arcsec/pixel (it should be around 3.5). I will be taking the scope down to the observatory in the coming weeks so first light shouldn't be too far away. Can't wait.

[[1ponders] (Paul)]

You're a cruel man Jase.


What a sweet looking setup.

[leon]

Good On you Jase,

If it is anything like mine and I'm sure it it's probably better, you will not be disappointed, they are an awesume scope, I just love mine, and they are built so sturdy.

Cheers Leon

[jase (Jason)]

Certainly didn't mean to be cruel Paul.

I'm certain the scope will deliver the goods Leon. Actually I wish I hadn't sold my original FSQ in the first place. Though it was a pre-N version (so no retractable dew shield), but was optically sound. There is not a huge difference between the new FSQ-ED and the original. I would have been happy to pick up a new FSQ-106N, but could only get second hand so decided to go for the new model.

Thanks again.

[RB (Andrew)]

What a gorgeous looking scope !
I've always had my eye on one of these, can't wait to see the results Jase !

[montewilson (Monte)]

Hi Jase - I have one of the original FSQ's. In fact, it's number 18 in the production run so I would be quite interested in comparing the performance of yours with one of the earliest.

I aslo have an STL-11000m so I think we can fairly compare the results.

I will post a picture of B86 that I took last week (2x5mins in Red). If you are able to take a similar picture we could compare them fairly and accurately.

It would be very interesting. I can't imagine that there would be a significant difference but none the less I am quite curious.

[jase (Jason)]

Thanks Andrew

Monte - Will definitely participate in a comparison test - would be interesting indeed. Though we will need to coordinate the testing criteria to minimise discrepancies. I think the easiest way to provide each other with the dark/flat calibrated FITS. Three subs should be provided to allow a median combine. I don't like using sum or average.

What's your average background pixel reading i.e how dark are your skies? This may also play a factor. I haven't measured mine for a while, but I will be shooting from a dark sky location. Would also suggest shooting through a luminance filter, unless we both are using the same manufacturers LRGB set. I'm using Custom Scientific. I think you have the Astrodon's so the light transmission curves will be different.

You're going to have to give me some time to get up and running as I took the time without a scope to re-grease the Titan RA and DEC worms. There maybe some minor fine tuning before I churn out any images. I will contact you when I'm ready for the comparison tests.

[montewilson (Monte)]

Hi Jase - Here are some links.

http://astronomy.proem.com.au/b86_900x600.jpg
http://astronomy.proem.com.au/b86_crop.jpg

In the above case the image was 2x10mins in RGB with the FSQ and STL. Image scale is 3.51"/px

I will do them again soon. How about this approach?

I will do 3x5 mins and then post you a disk with the images, my dark, flat and bias. That way you can eliminate any differences in the processing that could occur with our various methods and programs.

There is just a little too much data to do it online.

[jase (Jason)]

Hi Monte,
I'm not worried about the volume of data - we'll just use my website to transfer the information. The STL11k produces 20Mb files per exposure (1x1 full frame) so worst case scenario we'll be uploading ~100-200 Mb. I have plenty capacity. I'll set you up with an FTP account - will send the details/instructions via PM when I'm ready.

There will still be room for error unless you provide me with all you raw flat and dark frames - not just the masters. There can a quite a difference in noise/image quality depending on how many dark/flat frames are combined into the master. An interesting test was done to validate this - http://www.darkhorseobservatory.org/...2mar07_021.htm

I suggest we calibrate the files before uploading, but note the master frame information i.e master dark is a median combine of 20 darks etc, etc. Lets collaborate once I get things up and running to discuss this in further depth.