Ross1204

@Uranium235

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Dont try that TS M54 adaptor mate, its M54 thread is too short (mine nearly fell out, with camera attached!). I replaced that with a custom built M54-M48 adaptor with a much longer M54 thread, its basically:

This:

http://www.teleskop-express.de/shop/product_info.php/info/p4744_TS-M48-tilter---Tilting-compensation-for-field-tipping-in-astro-photography.html

Allen screwed to this:

http://www.teleskop-express.de/shop/product_info.php/info/p4147_Skywatcher-short-design-2--adapter-for-Crayford-focusers.html

The thread for the custom adaptor is here:

http://stargazerslounge.com/topic/215645-skywatcher-focuser-mod-mkii/?hl=%2Bfocuser+%2Bmod#entry2311103

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Would you say the threads on this adapter would be suitable for securing just a DSLR?

I am assuming you had a dedicated astro camera and filter wheel making the demand for a longer M54 thread imperative? 

Ross

Thanks for the reply @michael8554

Not entirely sure if this is right but I'm thinking something like this.

The above is all founded on this line in the description I've highlighted. 

I assume that this means it will add 2.5mm into the optical path? 

If so this brings me to 57.5mm spacing right?

Ross

Hi,

So I've been having an issue with what I believe to be camera tilt when connecting my DSLR to the stock dual speed crayford focuser of the Skywatcher 130pds. 

I removed the standard thumbscrew connection and replaced it with a compression ring adapter which I believe is still tilting the Baader coma corrector when tightening. The barrel of the corrector has a raised section which is not allowing the corrector to sit square within the compression ring.

So, this has led me to look around and see if there is a way to connect the camera through some sort of threaded setup. I have found an adapter which allows you to screw in to the drawtube which will provide a M48 connection for the coma corrector and a T-2 connection for the Canon T-ring. 

I have created a picture to illustrate the potential setup.

Adapter link - https://www.teleskop-express.de/shop/product_info.php/language/en/info/p203_TS-Optics-M54x1-to-T2-Adapter-fo-Skywatcher-Crayford-focusers.html

Does anyone know if this would work?

Would I likely have to correct the spacing somehow?

Thanks for reading.

Ross

20 hours ago, Stub Mandrel said:

How are you attaching the camera?

A T2 to 2" nosepiece and a T2 to Canon adaptor should work just dandy.

I use the 2" coma corrector with a T2 adaptor.

If you use a 1.25" nosepiece using a 2" to 1.25" adaptor as well may be adding too much length.

 

Hi,

I am currently connecting the DSLR (Canon 700D) to the scope via a Baader T2 adapter and Baader MPCC Mark III Coma Corrector.

I have been having trouble with what I believe to be camera tilt in the focuser when securing the DSLR via a compression ring fitting I brought.  I have also seen people suggest drilling a third thumbscrew hole in the stock fixture but would just like to rule out the Rotolock first.

Hi, 

Having just seen this on Flo's website I was thinking whether this would be a suitable solution for the 130pds. 

I have already tried the M54 Baader click lock which placed the camera just a tad too high to find focus but looking at the pictures I believe this maybe slightly smaller.

Does anyone have any experience  with this lock or any idea if it may work?

https://www.firstlightoptics.com/adapters/william-optics-2-rotolock-for-zenithstar-61-m54.html#

On 06/10/2018 at 14:55, bottletopburly said:

 

Thank you for going to the effort to get this picture, very much appreciated. I can definitely see the benefit of circulating the air inside the scope its just I can't help but think I will also need some heat somewhere.

On 06/10/2018 at 18:47, david_taurus83 said:

As promised:

Thank you for going to the effort to get these pictures, very much appreciated. I have never seen a secondary heater like that before so has definitely opened my eyes and I'm sure the wider community who may stumble across this thread. Looks nice and neat also with the power cable firmly secured to the spider vane, zero interference to the final image.

On 06/10/2018 at 20:11, Buzzard75 said:

As has been suggested, you could build your own solution. If you don't want to build your own, contact Kendrick with the measurements of your secondary and they may be able to make a suggestion in regards to their products. I had questions about my setup as well and they were very helpful. Not that you need it, but I can vouch for their products. I have one on my primary and secondary of my dob. I also have one for my Telrad and my eyepieces. They work really well.

I have emailed Kendrick to see what they can do but I believe it is their Thanksgiving holiday so hopefully get a response when they are back. Looks like it might well need to be custom job because the secondary on the 130pds is obviously on the smaller size and from what I have seen most of the off the shelf secondary heaters are too big.

16 hours ago, Captain Magenta said:

Re: the hairdryer:

I found that simply pointing the airflow at the secondary at an angle from the front of the scope through the spider was enough to very quickly clear it. The airflow "wraps" around the whole assembly quite well. Being very careful of course not to touch anything with it. Similarly for the eyepiece itself, I suffer from eyepiece fogging at the same time, and blowing the eyepiece worked just as well.

Cheers, M

OK thanks for letting us know it can work via the main OTA opening. The thought of not having to remove the camera is good to know, although it is a damn sight easier to see how dewed up the secondary is if you remove the camera. I guess it would help to let the scope settle for 5mins or so to let any tube currents equal out also. 

15 hours ago, bottletopburly said:

Try fitting a  pc fan to the back of the primary blowing air up ota.

Thanks for reply. 

Now assuming the fan wouldn't provide any heat to aid dew removal just the very fact air is circulating in the tube can be enough? Maybe OK for mild dew accumulation but not heavy build up? 

Also not entirely sure how I would fit such a fan, Google to the rescue..... 

13 hours ago, BigRD said:

I fitted the dew strap around the circumference. It's effective enough to keep the dew away and low cost too. ?

Would I assume you placed the dew strip over the thicker white section as surely the spider fixings get in the way in getting the heater closer to the secondary? 

Kinda like this picture. 

6 hours ago, upahill said:

I don't know how big the mirror is on the 130pds, but I would be looking into building a resistor based heater to go directly on it at this stage if a commercial one isn't available.

This site has some great information on building your own, and you can control how much power then.

http://www.deepskywatch.com/Articles/newtonian-dew-heater.html

Thanks for reply.

Thanks for providing the link I shall definitely take a look. I have never really made anything like that before so hopefully its not too steep of a learning curve as would like something pretty sharpish. 

6 hours ago, BigRD said:

I also have a 130PDS. I soldered together a resistor ladder type dew strap and fitted it around the front opening of the OTA and it works at treat. I control the temp using a PWM adjustable controller 

Thanks for reply. 

Now when you say 'front opening' of the OTA is that just positioned like a standard dew strap around the circumference? Or located somewhere around the secondary?

5 hours ago, Captain Magenta said:

I have sequestered one of my wife's old hair-dryers after similarly frustrating sessions. It's a total game-changer, and if it contaminates viewing slightly because it's heating up the secondary and/or the spider-vanes, although I haven't noticed it,  it's something I can live with for the sake of making the difference between that and seeing nothing at all.

Cheers, Magnus

Thanks for reply.

Yeah I have also looked in to getting one as really cheap and already have the ability to power outside. How do you actually use it though, do you direct the heat in to the front of the scope or down the focuser directly at the secondary? The thought of removing the camera to directly target the secondary seems like it could get boring quick, not so much maybe if your doing mostly visual as removing a eyepiece isn't as much of a big deal.

5 hours ago, david_taurus83 said:

The previous owner of my 200p fitted a resistor block to the back of the secondary and ran a thin wire out along the spider vanes to be powered by a 9v battery. I've never used it but he said he could stay out till early morning without any build up on the secondary. I will take a pic later this evening.

Thanks for reply.

Ok that sounds interesting, I like the idea of powering with just a standard 9v battery. With regards to the picture it is entirely up to you, don't feel you have to if too much hassle.

Hello,

So as the title of the thread says I am consistently suffering from bad dew formation on the secondary mirror (Skywatcher 130pds) which has stopped multiple nights of imaging after barely an hour or so.

I would like to think I have done a fair amount of research on the topic but unfortunately I am still unsure of how to deal with the problem. I initially brought a dew shield which I believe has slightly prolonged the inevitable for a short while but unfortunately has not solved the problem. After the shield didn't help I brought a wrap around dew heater (https://www.365astronomy.com/dew-heater-strip-for-newtonian-telescope-secondary-mirror-small.html) which is unfortunately too big for the secondary mirror stalk.

I have also seen that Kendrick and some others do stick on dew heaters which are glued to the secondary itself but again I believe the mirror on the 130PDS to be too small for their smallest product so yet again this is not the correct approach.  

So after these failed options what is left for me to try?

Maybe a dew strap around the OTA at the front? Look in to making my own strap?

Lastly I have read people use a 12v hairdryer to remove dew but as I am not doing any visual astronomy I don't think this would be a good solution as removing the camera would mean re-focusing every so often wasting imaging time.

Any help would be much appreciated as this problem is causing quite a lot of bother by ruining many imaging sessions. 

Ross

6 hours ago, Adam J said:

Its not the best way of going about it because the change in temperature of the tube will muck up your focus as you are also heating the entire tube. You are better off with a dew shield. 

One thing I would say about dew on a Newtonian is that I got it constantly as you do, then once I got an observatory I have not had it happen once. Its a roll off roof so the scope is still exposed. I think its more associated with taking a warm scope out of the house. If you can keep the scope in a unheated environment such as a shed it will help you no end. 

Adam

Unfortunately I don't see an observatory on the cards anytime soon so still scouring the internet for the best solution for the 130PDS. 

There are a few different heater options for the secondary on Newtonian telescopes but I think the secondary on the 130PDS is too small for this Kendrick heater.

I did read on one retailers site they stated the minor axis of the 130PDS to be 47mm which is obviously too small for this heater unfortunately.

So with this being said you also have the option for something like this.

https://www.teleskop-express.de/shop/product_info.php/info/p8571_AST-Heater-for-glued-Newtonian-secondary-mirrors-with-holder-D-31-mm.html

But again I am unsure whether this is the right size and would be suitable. 

I currently own this Dew Shield but unfortunately the secondary has still slightly fogged up, granted way less less than without it so definitely helps a bit.

https://www.telescopehouse.com/accessories/dew-removal/omegon-5-dew-shield-145-165mm.html

Ross

1 hour ago, Stub Mandrel said:

Probably about a minute, directed in the end at an angle so it 'swirled' around the tube rather than at the mirror.

I have no idea if this is the best approach, it just seemed appropriate.

OK that make sense. I always find it hard to see the mirror fog on the reflection from the primary but I generally know something is wrong by the histogram slightly moving more to the left the worse it gets. 

5 hours ago, Stub Mandrel said:

Yes it's glued on, not held by clips. I use a long dewshield from camp mat and rarely have dew issues. On two very damp nights I've used a heat gun on a low setting to clear the secondary.

Thank you for the reply. 

Out of interested if I were to use a hairdryer or heat gun do you need to remove the camera and direct low heat directly on to the secondary or can you just direct the air straight in to the ota? 

Also how long roughly would you say you need to use it to clear the mirror? 

Ross

Hi,

I have recently started to get the secondary mirror on my 130pds dew up pretty fast and am wondering if one of these heaters would be suitable? I am just a little unsure on how to measure the stalk as there are two sizes available. I also already use a dew shield  which has helped but not stopped the problem on the bad nights. 

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p8593_AST-Heizmanschette-fuer-geklebte-Fangspiegel-mit-Halter-D-50-mm.html

https://www.teleskop-express.de/shop/product_info.php/info/p8571_AST-Heater-for-glued-Newtonian-secondary-mirrors-with-holder-D-31-mm.html

The product also states for a 'glued secondary mirror' is that what the 130pds has?

Any help would be much appreciated.

Ross

16 minutes ago, ejp1684 said:

Don't know if this is what you're looking for. I've only recently bought an HEQ5 mount, and I'm learning about EQMOD so interested in any problems which may arise.

http://welshdragoncomputing.ca/eqmod/doku.php?id=faqs_-_park  third FAQ.

Eric.

Thanks for the link Eric, Much appreciated.

How do I reset the “Park to Home” position?

If you have a mount setup with invalid park data, you can get a fresh start by the following procedure:

(You will know that you have invalid RA/DEC park ring counter values if you execute a “Park to Home” and mount does not end up at the home position)

1) Unpark Scope using the EQMOD driver.
2) Shutdown EQMOD then power down the mount. Don't use park for this step.
3) Position the mount in the home position.
4) Power up mount
5) Start EQMOD & connect to mount.

The above steps will reset park settings of EQMOD.

Don't suppose yourself or anyone knows when it says 'Position the mount in the home position' if that means manually just the spirit level and setting rings?

Ross

Hi,

I believe my telescope is out of sync from the home position as I did not return there before turning the mount off.

Is there an easy way to reset that position in EQMOD?

I know how to use the level and setting circles to define the position on the mount just not sure how reset EQMOD so its all back in sync.

Ross