Would you drill a hole in a Takahashi?

[andrew s]

Or thermal management of a Takahashi Mewlon 180c. 

I am probably, going to get one of these but @JeremyS and others have pointed out some cooling down issues. So what can be done? With my home made Newtonians, adding cooling fans was a breeze, however, it would mean surgery to either the tube or rear casting of the Mewlon.

One technique used at some major professional observatories is to refrigerate the whole telescope enclosure. This could be possible but I was considering a less extreme idea. That is keep the telescope in a temperature controlled box with the set point set at the predicted night time average temperature or, whenever the predicted temperature was at the time I was planning to observe.

I have used an air to air peltier cooler and PID controller to temperature stabilise a spectrograph so it could be repurposed to do this.

Has anyone tried this or similar? If so I would love to hear how it went or any other views on this idea even if you have not tried it.

Regards Andrew

[JeremyS]

@andrew s, there is an excellent review of the Mewlon 180 by Roger Vine here. He makes the point that some of the larger Mewlons have ventilated cells built in. Those "holes" are pretty large 🙂

 

[mikeDnight]

Hi Andrew,

Having never used a fan to cool a scopes optics, I'm assuming you don't run the fan while observing. If that's the case, would making a front aperture cover with an air inlet and fan assisted air outlet help in cooling the Mewlon without having to drill holes in the cell? The cover would be removed for observing obviously.  Or simply devising a way to keep it at outside temperature may be enough. Having said that, I've used many 180 Maksutov's that didn't seem to need a great deal of time to cool.

[paulastro]

I'd drill a hole in it, but then I'm a SkyWatcher man 😄.

[Paul73]

I’d live with the cooling issues......

[andrew s]

55 minutes ago, Paul73 said:

I’d live with the cooling issues......

No chance. Regards Andrew 

[mikeDnight]

1 hour ago, paulastro said:

I'd drill a hole in it, but then I'm a SkyWatcher man 😄.

MODERATOR'S -  paulastro mentioned Skywatcher on a Tak thread!  Is this allowed? 

[mikeDnight]

To be honest Andrew, I'd have no issue with a fan being attached if its been done carefully and without compromising the scope. Peter Drew would probably be happy to drill your cell if you've any doubts. I don't imagine it would affect the resale value, and if you're going to keep the scope forever, then it wouldn't matter anyway. I'd do it with a good conscience! 

[Dr Strange]

I own the 210 and the 250. Only the 250 has active cooling. To cool the 210 (or for that matter your future 180) you don't need to drill holes. Simply place part of a bed sheet or other similarly thin cloth over the front of the tube then use a table fan or desk fan to blow air into the tube. This is what many do to cool down their Mewlon's. Thermal Equilibrium is not as big of a challenge as it is on a Mak or SCT because there is no meniscus preventing cool air from entering and warm air from leaving. 

That said there are a few cases where people have drilled holes in their Mewlon to add a fan. While I would not do it as I said others have. A Google search will put you on the right path.

[John]

I've tended to avoid scope designs that need a lot of cooling time even if they are excellent.

This Mewlon owner dealt with it by keeping the scope at close to outside temperature in a sealed box:

https://www.cloudynights.com/articles/cat/user-reviews/takahashi-mewlon-210-review-r2713

 

[andrew s]

1 minute ago, mikeDnight said:

To be honest Andrew, I'd have no issue with a fan being attached if its been done carefully and without compromising the scope. Peter Drew would probably be happy to drill your cell if you've any doubts. I don't imagine it would affect the resale value, and if you're going to keep the scope forever, then it wouldn't matter anyway. I'd do it with a good conscience! 

Thanks. I will try the thermal box first. However, if I think it needs it it will go under the knife.  For me it's all about function. You should have seen my home built Newtonians . Nothing to look at but held collimation even after drilling 3/4" holes.

Regards Andrew 

[dweller25]

This could be a cheap and non invasive option........

[andrew s]

21 minutes ago, dweller25 said:

This could be a cheap and non invasive option........

Not exactly sure where you think I should put it.

Regards Andrew 

[dweller25]

Well Andrew ...... 🤣🤣

I am experimenting with it on the front of a 6” Classical Cassegrain, purely to cool the primary quickly before viewing.

In late February it took a 35 minute cool down time using the fan to get a star plus diffraction ring showing steady at x464.

Edited June 8, 2020 by dweller25

[Peter Drew]

Holes drilled in tubes and tubes cut to length to allow the use of binoviewers while you wait.  Anything from the ones paulastro dared to mention on this thread to Takahashi's.       

[Alien 13]

Drilling holes in a scope is never a problem if you keep a scope forever but I would imagine a hole in a Takahashi would devalue it by 50% or more much more.

Alan

[Marvin Jenkins]

It’s just a telescope! Drill a hole in it!😂 old school cyclist. Back in the day some of us would drill huge amounts of excess aluminium out of very expensive cycling equipment to save a few grams. Drillium is what I think it is now called.

In all seriousness, my hands would tremble at the idea of drilling a hole in something Astro high end, but they are just telescopes in the end not Holy Grails.

Marvin

[Gorr_77]

DRILL, DRILL, DRILL... a bit chanting :)......

 

Drill it!!! ... use smaller fans from C14 kit... or something like silent /no vibration fan : 30x30 / 40/40 with mesh filter:

 

[JeremyS]

Or if the cool down is really slow:

[JeremyS]

Or maybe this for a sophisticated man like you , Andrew 🙂

Edited June 8, 2020 by JeremyS

[andrew s]

Stop it @JeremyS your a very naughty boy.

Regards Andrew 

[JeremyS]

Actually I’m really excited that you might go ahead with the Mewlon, Andrew.

Perhaps when Mars is around later in the year, and assuming it’s allowed, we could do a side by side with my Tak TSA 120 🙂

[andrew s]

52 minutes ago, Marvin Jenkins said:

It’s just a telescope! Drill a hole in it!😂 old school cyclist. Back in the day some of us would drill huge amounts of excess aluminium out of very expensive cycling equipment to save a few grams. Drillium is what I think it is now called.

In all seriousness, my hands would tremble at the idea of drilling a hole in something Astro high end, but they are just telescopes in the end not Holy Grails.

Marvin

I still have a Pace RC200 mountain bike with the custom rectangular aluminium alloy frame with indents to save weight. No need for the drill on it.

Regards Andrew 

[andrew s]

7 minutes ago, JeremyS said:

Actually I’m really excited that you might go ahead with the Mewlon, Andrew.

Perhaps when Mars is around later in the year, and assuming it’s allowed, we could do a side by side with my Tak TSA 120 🙂

Certainly, it would be fun. 

Regards Andrew 

PS not sure I could bring myself to look through a refractor!

Edited June 8, 2020 by andrew s

[JeremyS]

1 minute ago, andrew s said:

I still have a Pace RC200 mountain bike with the custom rectangular aluminium alloy frame with indents to save weight. No need for the drill on it.

Regards Andrew 

Just to be clear, the side by side comparison is for the two scopes, not you and me on bikes. No way I could keep up you with your current level of fitness 🙂