PGM

2 minutes ago, John said:

A Powermate, TeleXtender or Focal Extender (Tele Vue, Meade and ES products) move the focus point either not at all or very little.

That's interesting, I didn't know that. I might buy a 2.5x Powermate to try it then.

3 hours ago, Nakedgun said:

The short-throw focuser on the DC can make finding the right combination a trying experience. Diagonals from different manufacturers will not all have the same focal length, nor will all barlows. I found this shorty barlow to be helpful. To use a "regular" length barlow I have to change extension combos.  An observing associate with a variety of ep/barlow/diagonal choices can save some time and aggravation.

 

 

 

Absolutely! My barlow is also a shorty (Celestron X-Cel ED Barlow 2x) but I had no luck with it. Unfortunately where I live I know nobody pursuing visual astronomy who could help, and I can't keep buying more and more equipment just to try it once and resell it.

On 13/01/2019 at 10:21, John said:

Usually with a barlow in place, you need to find a bit more inwards focuser travel to reach focus. Is that your problem - lack of enough inwards focuser movement ?

The X-Cel ED barlow goes betwen the diagonal and the eyepiece I believe - is that where you are putting yours ?

Edit: could you post a photo of the focuser end of your scope as you have been using it so that we can double check on the componants. The Tak diagrams are all well and good but it's not all that clear which adapter is which.

 

Hi John, sorry for the delay, I thought I had already answered.
Yes, diagonal » barlow » EP.
That's right, I'd need more inwards movement. Anyway, I have 7 EPs, so I'm giving up on barlows for as long as I keep the stock DC focuser. I hate the idea of having to screw/unscrew adapters while watching something.

I wonder if any Tak FC-100D owners could help me with yet another focusing problem. Previously I could not bring any eyepiece to focus, but @mikeDnight told me to remove the #81 adaptor and that solved it completely. Now I purchased a barlow (Celestron X-Cel ED Barlow 2x) and I can't achieve focus. I've tried with and without the #81 adaptor.
Any suggestions?

48 minutes ago, mikeDnight said:

Yes, it seems to be 81 that might be throwing your focus too far out. 15 should screw directly onto the draw tube and all should be well. I don't know why Takahashi insist on supplying these adapters. I'm sure it would be simpler and cheaper to just have a longer draw tube. 

Mike, it worked! Thank you! I noticed a small opening in the clouds, hurried to get everything in place and there was beautiful Luna in-focus and fighting the clouds ?

So just in case this helps someone else, the manual's DC diagram does seem to be incorrect - the diagonal branch should come before part 81, ie:
- w/ diagonal: 15+14+46+diagonal+EP
- w/o diagonal: 81+16+15+14+46+EP

So simple, and yet I never would have tried going against the manual. Lesson learned.

I can't thank SGL enough for the help I've been getting...

2 hours ago, Highburymark said:

It will just be a question of finding the right adapters to allow you to reach focus with the diagonal. One of the features of the Takahashi focuser is very limited travel, which means you need to get the spacers/adapters right. 

How does one calculate the right parts? I was planning to give the Tak focuser a chance before getting a FT focuser, but this might settle it.

2 hours ago, mikeDnight said:

It's interesting that you say the latest user manual makes no mention of alcohol! 

None I could find ?

1 hour ago, mikeDnight said:

Did you have the extension tubes attached? If so, you'll need to remove them. The set-up should look like the attached picture when a diagonal is used. In this mode the scope should focus pretty much all 1.25" eyepieces. You might like to try and focus on the distant horizon before you aim it at the night sky, at least until you've acquired a finderscope of some sort. 

It's interesting that you say the latest user manual makes no mention of alcohol! 

Great scope by the way!! 

 

Hi Mike,

My DC did not look like that! I used adapters 81+15+14+46+diagonal, and you seem to be going without part 81 - if I'm seeing it right. Can the manual be wrong? That's great news, I'll try that tomorrow! Too cloudy tonight...

6 minutes ago, Stu said:

Great setup PGM! Just a few teething problems to sort.

When you say you saw nothing with the prism in the light path,  could you see a bright refocused moon or just darkness? I'm guessing it was more a finding issue,  best get at least an rdf sorted so you can find things more easily then go from there. You should at least see bright moonlight through the eyepiece even if way out of focus. 

You with get there.

Thanks.

When I used the diagonal, the sky was not completely dark yet, so I could definitely tell apart the dark blue sky and a completely defocused whitish surface (which I took for clouds, but later on guessed it was the Moon). It was just completely out of focus, like a white wall.

Hello,

Well, yesterday was inauguration day for my Tak! ? ...and also for me as a scope operator.

The full set-up I used consists of:
- Takahashi FC-100DC (stock, but no finder scope)
- Takahashi clamshell + Vixen plate
- Berlebach Dovetail Clamp with Pressure Shoe
- Giro Ercole
- Gitzo GT5533S tripod
- Baader T-2 Amici Prism Diagonal BBHS
- Baader BGO 18mm / 6mm
- Celestron X-Cel ED Barlow 2x

I purchased this Baader T-2 Amici Prism Diagonal BBHS because I love the Moon so much that I can justify having a dedicated diagonal just for it. However, I do intend to get a second-hand Baader T-2 Zeiss Prism BBHS when I find one for sale in excellent condition.

The BGOs 18/6mm are the only EPs I have at the moment, but I have a few gems on the way (TV Panoptic 24mm, TV Plössl 8mm, Pentax XW 7/5/3.5mm).

The clouds that had lasted for many days were mostly gone but seeing was far from great. Just as I was starting to extend the tripod legs, one of them came completely off, along with some inside parts. This problem stole valuable time (and calm!) from me, but was eventually fixed with the help of two SGL members, as posted in another topic.

So now the whole set-up was ready to go, with a BGO 18mm on the spot. I pointed in the Moon's general direction, took a peek, adjusting the focuser... nothing. I checked the diagram on the manual, and concluded I needed to take out the aux. ring adapter because I was using a diagonal. Did that, took another peek, changed EPs... still nothing. I remembered reading a few posts about light path issues, so assumed this might be one of those problems (which I still don't fully understand, to be honest). So I decided to go Japanese-style, removing the diagonal, adding the aux. ring, to look directly through the tube.

By this time, the Moon and Mars were already low, and seeing was not helping either. I pointed the 18mm at the Moon, took a peek... and there was Luna upright in all its glory! ? I could see the unstable air waving in front of it, but still, very clear, and obviously closer than with my binos (even if not as convenient!). Very nice indeed.

Time was of the essence, so a few minutes later I searched for Mars, and this was much trickier than I expected, because I have no finder scope. I have some knowledge of where many objects and constellations are, but I'm just a beginner and so the reversed image orientation and the first-time handling of the mount were harder than expected. Many times I found myself searching aimlessly. Still, all part of the experience curve, I'm sure. I eventually found Mars with the BGO 18mm, and also Sirius, Rigel, and a few other stars, but many other targets were impossible to find and identify - most were also too high in the sky to look without a diagonal (at this time I was breaking my neck and back doing yoga stances on the ground ?). The BGO 6mm was almost impossible to use. I enjoyed using it briefly on the Moon, but could not use it on anything else. I tried focusing a star on-axis with the 18mm, tightening the mount's clamp, and exchanging to the 6mm without shaking the scope (other than unscrewing the Tak focuser's ring), but no success, could not see a thing with the 6mm. I'm certainly doing something wrong...

Ok, now back to my Amici diagonal. According to Baader's website, it has a 47.5mm optical length. Can anyone please explain what I need to make it work?

Lastly, regarding the controversial Takahashi lens cleaning. Some topics on SGL and CN mention that the manual indicates alcohol is to be completely avoided, which some members attribute to a wrong translation from Japanese. My Tak is brand new, so maybe the manual has been corrected/updated - it has no mention whatsoever about alcohol.
Care & Maintenance highlights:
- large hand blowers are recommended;
- canned air is strongly disapproved;
- "Use pure cotton swabs slightly moistened with lens cleaner and gently remove any dirt"

Well, clouds are back today. Hopefully they'll clear for 46P tomorrow night...

Thanks for looking!

Very nice pics. The previous night, the Moon, Venus, and Spica were forming a lovely triangle. The following night the Moon lagged behind, producing that beautiful line-up.

Never tried a Zoom, but did some research a few months ago about them. There seems to be a trade-off between performance (they tend to have a worse FoV, exit pupil output, and image quality) and convenience (may be very useful for Moon, Planets, and the Sun, because a smooth change in their focal length allows the observer to quickly find the optimal useful magnification in a changing atmosphere, without taking the eye from the EP).

2 models seem to come up the most:

- Baader Hyperion Zoom 8-24mm
- Tele Vue Zoom 3-6mm

I also found a post from someone using 2 Zooms with a binoviewer, but BVs are a different topic - I suggest opening a different thread if you're interested.