Dew a little help.

[alan potts]

Dew,

Now this is a newish thing for me here in Bulgaria. I have a fair few scopes and it seems as if it is affecting the M/N 190mm (probably the 180mm Mak as well) and the SC 12 inch.

I have only had dew once on the 12 inch and that was many moons back when it got cold very fast over an hour or so. Lateley I have had dew showing up on these scopes even though they are all outside.

The other night dew cropped up after 40 mins and on the M/N and I switched scopes to a refractor which are not affected it seems .The M/N for example, when I put it away the dew went off the collector after 20mins even though it was still at the same temperature, only difference was a roof overhead.

Now I have coming an 18 inch open tube Dobsonian and after Christmas a scope from Orion ( 10 or 12).

I am looking for tips to help out here as I am new to this issue and possible built-in heater for the Newtionians, do they work and are they easy to install. any other tips and advice will be greatly received.

Sorry if it seems a dumb question but I always believe in asking those who know.

Alan

[Rustysplit]

As you are getting your canopus built now Alan, I would ask Michael to fit a secondary dew heater as he goes. I have yet to see a truss dob that does not succumb to dew eventually. Well worth it and very effective. I know that some worry about tube currents and such, but dew will end a session dead whereas a tiny bit of heat turbulence will die down and you can carry on, if you even notice it?

[faulksy]

I built heaters for my dob alan very easy to make. I have one fitted to the finder both ends,the secondary and eps. You can buy all and fit yourself,make your own, or as rusty says get Michael to pre install one now, you won't regret it. Also orion will fit and supply as well

sent from my fone using fingers

[NGC 1502]

Hi Alan. I've had the secondary dew up on my Newtonians a few times.

Much more of an issue on open tube scopes (needs a shroud), than solid tubes.

One way to sort it, as long as the dew is just a misting over, is to point a 12v dew gun down the focuser, after removing the eyepiece. If the dew has formed droplets, it's too late for that to work.

A better solution is something like this - http://www.kendrickastro.com/newtonian.html - because prevention is better than cure.

Regards, Ed.

[alan potts]

I already have sent an e-mail based on Alan and Ed's point as there is no way I can put a heater strip under a secondary after it's been glued, this needs to be done now. He is only just starting the build so I should be in time.

There are a few things that I could have done that I didn't know about, I guess most of his customers are already Dobaholics and know all the ins and outs. I only know pictures.

I maywell ask Orion to do the same thing with whatever I get from them.

Alan.

[CountBorgula]

As I mentioned in my other thread, I found a hairdryer worked well for clearing off the secondary mirror.  In actual fact my primary never dewed up last night, and I am wondering if the addition of light shroud and dew shield might solve my problems entirely, without the need to fit anything to the secondary?

[Rustysplit]

Good call Alan. Gotta be the easiest and most convenient solution.

[alan potts]

The Count came up with the Hair dryer which may do for the Mak/Newt, I think just an extension sheild would maybe stop dew on that, looks easy enough to make something. I am sure it is only because of the massive rain we have had this year that I am having these problems, I have not seen dew really before like this.

In winter the humidity goes down to 25% at the moment it's 88% and in summer about 38% is the daily norm, so you never really get the problem, this summer though the normal day humidity was about 60-70% though so hot most of the time never a problem.

I must try and get something made to wrap aroung the Sumerian as well, just need to find out the best material and my wifes friend can run one up on the machine. Maybe as nice fur for those chilly nights, don't want it getting cold do we.

Alan

[Rustysplit]

For a shroud, stretchy lycra fabric works well, fleabay is full of the stuff. I used ripstop nylon for mine and stuck it all together using that easy hem iron on stuff?? The stuff you can use to hem clothes without sewing? I then taped all the seams with ripstop repair tape. I did promise myself that I would get it sewn up properly.....that was nearly 2 years ago!

[niallk]

I believe the Canopus comes with a secondary dew heater as standard, from what I've been reading on the Sumerian website...

[Scooot]

I already have sent an e-mail based on Alan and Ed's point as there is no way I can put a heater strip under a secondary after it's been glued, this needs to be done now. He is only just starting the build so I should be in time.

There are a few things that I could have done that I didn't know about, I guess most of his customers are already Dobaholics and know all the ins and outs. I only know pictures.

I maywell ask Orion to do the same thing with whatever I get from them.

Alan.

Hi Alan,

The Sumerians come with secondary dew heaters as standard. Michael told me the other day it's a resistance wire powered by 4 AA batteries, I presume yours will be the same.

Whoops sorry Niallk didn't read your post properly.

[niallk]

No worries Scooot - if you don't mind me asking - are you getting a Canopus built? I'm pretty interested in possbly going down this route too!

I'm certainly looking fwd to your 1st light report too, Alan!

I've posted another thread seeking comments on the mechanical behaviour of the Canopus (and DL)...

All the best

[alan potts]

Thanks, you two, If that is the case then I need not worry. With me I sort of made up my mind on the maker of this scope about a year ago, add to that the mirror did not come from his normal suppliers and reading between the lines, or not as the case was I just asked if he would make an 18 inch for John Nichol's mirror, the rest is history.

I think the build is underway as of now but I have told him I am in no hurry, I just want a well made quality scope, I'm sure he will deliver. I imagine then I am back to the buy a Dob and then rebuild it on a somewhat smaller scale, Dan pointed out the FT and SIPS focuser that I would have liked but I can grow into that at a later date, Don't even know if I can hack it with the Dob Mod yet after years of GOTO tech, 'we will just have to wait and see" in the words of Sir Patrick.

Thanks for the details on the cloth and I have just ordered mink.

Just seen that, First light will be a detailed account as i always try to put together, more of a first second and third light.!

Alan

[Scooot]

No worries Scooot - if you don't mind me asking - are you getting a Canopus built? I'm pretty interested in possbly going down this route too!

I'm certainly looking fwd to your 1st light report too, Alan!

I've posted another thread seeking comments on the mechanical behaviour of the Canopus (and DL)...

All the best

Yep, 16", shouldn't be too long now if they get a chance to test it.

[niallk]

Exciting times Scooot! They look like beautiful scopes crafted with passion, care and attention to detail - should be a great performer - will certainly be very interested in your reports

Alan, by all accounts your 18" scope will be fantastic with the Nichol mirror. If I do take the plunge, it would be for the 16", with the 1/10 wave OO mirror. Anything I should be aware of??? Not sure if I detect a slight concern with OO as the mirror provider - could have wrong end of the stick here - apologies.

Your reviews are always most comprehensive - the effort and detail you give is really appreciated! Certainly have helped me with my fledgling ep collection

[alan potts]

Niallk,

I don't know why but in the many e-mails between Michael and myself and I guess there must have been 20 at least. Micheal did say that it was strange that I was asking for a scope to be made with a J Nichols mirror, this was to me out of the ordinary, he told me he was going over to using Nichols mirror and this was a coninsidence to say the least and not a problem in any way.

Now why this is the case I don't know, I am sure Orion mirrors are up there with the best in terms of quality and from that point I see nothing to worry about. The only thing that I could say is maybe J Nichol's mirrors are a little cheaper. I got an F 4.3 mirror ( special offer for some reason unknown) that had been made and just needed coating, 3 weeks works and done at Orion, so JN seems to rate them in this way at least. My 18 inch was almost exactly the same as a 16 inch OO mirror, only a few beers in it.

Even if Micheal has not fully gone down this road yet I am sure he would help you out if you source the mirror, he did after all use a Dutch mirror maker up until they went out of business. I am going to buy an Orion scope for planetary work after Christmas and this will be a 1/10 PV scope, I am looking forward to the Sumerian but I do like driven scopes for planets. 

Hope this helps a little.

Scooot,

It will be nice to see a report from you on your scope, he seems to have a fair bit on at the moment, I imagine that there is a good deal of work in one of these things that shouldn't be hurried. My only worry is mine gets lost in the Christmas mail and yes i said mail, couriers here do deliver mail from UK.

Alan

[Scooot]

Niallk,

I don't know why but in the many e-mails between Michael and myself and I guess there must have been 20 at least. Micheal did say that it was strange that I was asking for a scope to be made with a J Nichols mirror, this was to me out of the ordinary, he told me he was going over to using Nichols mirror and this was a coninsidence to say the least and not a problem in any way.

Now why this is the case I don't know, I am sure Orion mirrors are up there with the best in terms of quality and from that point I see nothing to worry about. The only thing that I could say is maybe J Nichol's mirrors are a little cheaper. I got an F 4.3 mirror ( special offer for some reason unknown) that had been made and just needed coating, 3 weeks works and done at Orion, so JN seems to rate them in this way at least. My 18 inch was almost exactly the same as a 16 inch OO mirror, only a few beers in it.

Even if Micheal has not fully gone down this road yet I am sure he would help you out if you source the mirror, he did after all use a Dutch mirror maker up until they went out of business. I am going to buy an Orion scope for planetary work after Christmas and this will be a 1/10 PV scope, I am looking forward to the Sumerian but I do like driven scopes for planets. 

Hope this helps a little.

Scooot,

It will be nice to see a report from you on your scope, he seems to have a fair bit on at the moment, I imagine that there is a good deal of work in one of these things that shouldn't be hurried. My only worry is mine gets lost in the Christmas mail and yes i said mail, couriers here do deliver mail from UK.

Alan

I think you're probably right about the mirrors, I suspect he's done a deal with JN. My mirror is going to be a 1/10 OO and I'm not concerned at all, my current OO is 1/10 so I have an idea of what expect.

Mine is almost due now but I've told him I'm more interested in it being right than it being rushed so I'm not really expecting it until well into December and even maybe the new year.

Yes I'll attempt a balanced report, I find them very useful when considering purchases and I know everyone is very grateful for your efforts in this regard.

[alan potts]

Richard,

It is going to look good for him if he lands two good reviews on the site and cannot do business any harm. I have told him I will send a copy of what I post to him and to JN, if they wish to use it on theirs sites they can. I will simply tell it as it is, if there are areas where I feel improvement can be made the I will write them. I have a very large experience of setting up production of products around the world and I always believe that as long as you balance a report even bad news is not that negative. The trouble it people always seem to focus on the one bad point and forget the many good points.

He must have hidden powers you know because I first priced an 18 inch scope up about 18 months back, it was the same type of scope but with 1/10 PV Huygen mirror and all the bells and toys on board. The cost was not too bad at 8,500 E I believe but a lot of this was the drive systems which I know now he does not offer, so maybe I did the right thing as I got the impression he had had problems with this . I declined and bought something else,  his last e-mail was something along the lines of "you will be back in touch as a Dob is for life".  He was right.

Alan

[faulksy]

Thanks, you two, If that is the case then I need not worry. With me I sort of made up my mind on the maker of this scope about a year ago, add to that the mirror did not come from his normal suppliers and reading between the lines, or not as the case was I just asked if he would make an 18 inch for John Nichol's mirror, the rest is history.

I think the build is underway as of now but I have told him I am in no hurry, I just want a well made quality scope, I'm sure he will deliver. I imagine then I am back to the buy a Dob and then rebuild it on a somewhat smaller scale, Dan pointed out the FT and SIPS focuser that I would have liked but I can grow into that at a later date, Don't even know if I can hack it with the Dob Mod yet after years of GOTO tech, 'we will just have to wait and see" in the words of Sir Patrick.

Thanks for the details on the cloth and I have just ordered mink.

Just seen that, First light will be a detailed account as i always try to put together, more of a first second and third light.!

Alan

alan theres always push to which me and scooot use. you can also add drives to it if need be, its a lot more accurate than any go to i have ever had as well, including my old/great cpc 9.25

[alan potts]

Mike,

Yes the Argo push too is on the shopping list and Micheal is fitting the mounting bits and pieces on for me. The thing was for this one I had to take 'She who is to be obeyed ' with me to the bank as it was an international transfer I and I wanted it right, my Bulgarian is not perfect, so I was hiding an 800 Euro outlay that will not be noticed later. Micheal has given me a list of what I need, there seems no malice with him at all. The other thing is I want to have a play first see how I get on with nudging, I may add a platform as well sometime.

Alan

[faulksy]

Mike,

Yes the Argo push too is on the shopping list and Micheal is fitting the mounting bits and pieces on for me. The thing was for this one I had to take 'She who is to be obeyed ' with me to the bank as it was an international transfer I and I wanted it right, my Bulgarian is not perfect, so I was hiding an 800 Euro outlay that will not be noticed later. Micheal has given me a list of what I need, there seems no malice with him at all. The other thing is I want to have a play first see how I get on with nudging, I may add a platform as well sometime.

Alan

sounds great alan, just a thought, argo navis is around £1000 the nexus which uses the same encoders,same hardware is only £400 here it is

http://www.astrodevices.com/products/Nexus/Nexus.html

[alan potts]

Mike,

Many thanks you have linked this to me once before. This is something that will be difficult to get here, for one I would need the trouble and strife to deal with the import. I do not like doing this one bit, the customs here go out of their way to be a pain they are a law unto themselves. I also do not like buying anything from the States, stuff made in America is different. This though I believe is Australian isn't it?

I will go with the Argo even if it is more, I can get this through my mate and he normally give me a price better than seen on site, though I don't expect it to be 400 quid. I think the Argo even with the encoders comes to about 700 Euros so thats about 550 quid is it? At least that way i do my bit to help the economy.

Alan.