Cordless Mini Heat Gun

[Westmoorland]

I'm not sure the relevant areal to post this but wondered what anyone might think about this product as a temporary dew solution.

https://amzn.eu/d/b8FuOcb

 

I need cordless because my extension lead isn't long enough and less wires the better. Cordless hairdryers only seem to blow cold air in cordless mode and bigger heat guns with the battery inc seem a bit pricey since I only need one for telescope dew. My concern is that the small nozzle won't blow out hot air over a wide enough area quickly enough to heat the corrector on my C9,25 SCT. 

 

Any members here think this is a good temporary buy?

[Steve Ward]

A dew shield would be a better bet surely ... ?

https://www.firstlightoptics.com/dew-prevention/celestron-dew-shield-for-c925-c11-otas.html

[Westmoorland]

6 minutes ago, Steve Ward said:

A dew shield would be a better bet surely ... ?

https://www.firstlightoptics.com/dew-prevention/celestron-dew-shield-for-c925-c11-otas.html

 

Yes, I have one by AstroEsssentials. However it only delays the inevitable dew which always invariably ends my viewing sessions. early.

I was thinking, after checking with the red torch: shield off, zap it with heat, shield on again.

[Elp]

This is all you need:

https://www.firstlightoptics.com/dew-prevention/celestron-dew-heater-ring-for-sct.html

 

[Westmoorland]

22 minutes ago, Elp said:

This is all you need:

https://www.firstlightoptics.com/dew-prevention/celestron-dew-heater-ring-for-sct.html

 

Brilliant: I bet I don't even need to plug in into anything, nor buy the dew temperature controller. 

[Elp]

It needs 12v power. I usually run it off an Asiair or my portable Celestron Lithium LT. A dew shield does help though as a first preventative measure.

[AstroKeith]

4 hours ago, Westmoorland said:

I'm not sure the relevant areal to post this but wondered what anyone might think about this product as a temporary dew solution.

https://amzn.eu/d/b8FuOcb

 

I need cordless because my extension lead isn't long enough and less wires the better. Cordless hairdryers only seem to blow cold air in cordless mode and bigger heat guns with the battery inc seem a bit pricey since I only need one for telescope dew. My concern is that the small nozzle won't blow out hot air over a wide enough area quickly enough to heat the corrector on my C9,25 SCT. 

 

Any members here think this is a good temporary buy?

Avoid like the plague. It blows air at about 150 to 100C. That will crack glass in a jiffy. (plus from the reviews it doesnt work reliably!)

 

[Westmoorland]

5 minutes ago, AstroKeith said:

Avoid like the plague. It blows air at about 150 to 100C. That will crack glass in a jiffy. (plus from the reviews it doesnt work reliably!)

 

 

I have a gut feeling you're right. What would you say about this typically more expensive model that allows for adjustable heat:

 

https://amzn.eu/d/csveu8p

 

[Westmoorland]

1 hour ago, Elp said:

It needs 12v power. I usually run it off an Asiair or my portable Celestron Lithium LT. A dew shield does help though as a first preventative measure.

I have the Celestron lithium battery power tank attached to my tripod leg. But the instructions state that the a/c power cannot be used simultaneously with the 2 USB ports. The other ports on the AVX are for satnav etc

 

How do I power the scope and the dew heater at the same time. That's what isn't clear. Sorry if I seem naive about this.

[Elp]

My Lithium LT is the same, usb power or 12v, not both at the same time. Either you need a dedicated 12v like how I utilise my Lithium LT or you need a power box controller like the Pegasus Astro type ones, the Asiair Pro/Plus/Mini are similar in that they have 4 x 12v outs but the added benefit is they're also fully loaded AP controllers. If not doing AP then something like the Pegasus box though an individual battery would be simpler.

Never, ever use a heat gun unless you need the specific targeted high heat. Because their heat is concentrated in a narrow beam you'll quickly melt anything in their path without even realising it.

Edited May 17 by Elp

[Westmoorland]

50 minutes ago, Elp said:

My Lithium LT is the same, usb power or 12v, not both at the same time. Either you need a dedicated 12v like how I utilise my Lithium LT or you need a power box controller like the Pegasus Astro type ones, the Asiair Pro/Plus/Mini are similar in that they have 4 x 12v outs but the added benefit is they're also fully loaded AP controllers. If not doing AP then something like the Pegasus box though an individual battery would be simpler.

Never, ever use a heat gun unless you need the specific targeted high heat. Because their heat is concentrated in a narrow beam you'll quickly melt anything in their path without even realising it.

 

https://www.widescreen-centre.co.uk/celestron-smart-dewheater-controller-2x.html

 

One of these?

[bosun21]

Just use a splitter cable from the LT supplying the Celestron dew ring and the other your mount. I did this for a period of time before buying another battery power source.

[Carbon Brush]

Another cautionary note on the 12V hair dryer or car heater type of product.

At switch on the motor takes a high pulse current. Depending on your 12V source, you may have problems.

A big car/leisure battery will be OK.

A small 12V lead acid battery in a powertank will dip momentarily.
The dip may upset the mount electronics, causing datum loss or other effects.

A small lithium battery in a powertank type product will suffer a similar dip to the small lead acid.
However, it may also trip the overload protection circuit, requiring a power off/on cycle to reset.

Assuming you survive all of the aove, the next potential issue is when you switch off.
The magnetic field in the motor collapses, generating a large negative voltage spike.
The 'sell for £1 less' products from China and the like do not have suppression components.
Hopefully things like the low resistance heater element in the hair dryer absorb the energy.
But, if you put a big negative spike on mount electronics or a computer, you may upset it, temporarily or permanently.

The only way I would use a 12V hair dryer around a scope is powered from a completely separate 12V battery.

HTH, David.

[Elp]

Doesn't a splitter lower the amps going to each branch?

Edited May 17 by Elp

[AstroKeith]

2 hours ago, Westmoorland said:

 

I have a gut feeling you're right. What would you say about this typically more expensive model that allows for adjustable heat:

 

https://amzn.eu/d/csveu8p

 

The risk from all heat guns is enormous. Dont go there.

It's really important to stop or delay at least the formation of dew in the first place. Once formed, the air dryers will clear it, but not for long. You're into an ever increasing cycle of trying to clear it.

There is no substitute for good dew heater bands or equivalent. Especially in our humid climate. Plus a dew shield.

[Westmoorland]

46 minutes ago, AstroKeith said:

The risk from all heat guns is enormous. Dont go there.

It's really important to stop or delay at least the formation of dew in the first place. Once formed, the air dryers will clear it, but not for long. You're into an ever increasing cycle of trying to clear it.

There is no substitute for good dew heater bands or equivalent. Especially in our humid climate. Plus a dew shield.

Yea, it's just I wanted a cheap temporary fix until I decide what the long term set up should be. I can't believe there's nothing cheap that I can plug into my AVX mount and not have to worry about more equipment.

[Elp]

You could try a standard dew heater band wrapped around the OTA usb powered. It just won't work as well as the ring.

[Westmoorland]

The USB ports on my power tank cannot be used while the A/C is powering the mount. 

21 minutes ago, Elp said:

You could try a standard dew heater band wrapped around the OTA usb powered. It just won't work as well as the ring.

 

[AstroKeith]

1 hour ago, Westmoorland said:

Yea, it's just I wanted a cheap temporary fix until I decide what the long term set up should be. I can't believe there's nothing cheap that I can plug into my AVX mount and not have to worry about more equipment.

For most users, managing dew is an essential part of the equipment, yet most manufacturers have omitted it as part of the standard kit. In the UK its like selling a car without windscreen wipers - useless.

Refractors have nearly always had an integral dew shield which went a long way to helping.
Newtonians benefited from having their main optics at the bottom of a tube.

But SCTs failed to address the issue. Perhaps they were all supposed to be used in California!

a 300mm long tube Velcroed  to your scope will get you a long way.

[Elp]

13 minutes ago, Westmoorland said:

The USB ports on my power tank cannot be used while the A/C is powering the mount. 

 

Just get a usb power bank, like ones for mobile phones but high mAh, they'll very likely cost less than any heater band you buy.

[Elp]

5 minutes ago, AstroKeith said:

But SCTs failed to address the issue. Perhaps they were all supposed to be used in California!

I think it's more to do with they don't look quite so appealing with a dew shield out front.

[powerlord]

usb power pack for 20 quid from amazon.

usb dew band for 15 quid from amazon.

you might need a wee extra bit of velcro to get it to reach around an SCT.

job done.

I use these ones on all my equipment:

https://www.amazon.co.uk/KIWIFOTOS-Temperature-Regulator-Universal-Telescopes/dp/B0861XRZH6/ref=sr_1_10?crid=3I20ZNTMOQOWX&keywords=dew+heater&qid=1684339471&sprefix=dew+heater%2Caps%2C66&sr=8-10

but these are good value - but only 100% power - prob fine for a big sct though - just use both:

https://www.amazon.co.uk/Fast-warm-Spliceable-Astronomical-Telescopes-Celestron/dp/B09D7FSHBH/ref=sr_1_4?crid=3I20ZNTMOQOWX&keywords=dew+heater&qid=1684339471&sprefix=dew+heater%2Caps%2C66&sr=8-4

 

[Elp]

The fantaseal ones are good, they don't draw too much power compared to others.

[Westmoorland]

I honestly can't decide what course to take. For now I'd be grateful for a link to a cordless hairdryer that blows hot air, since heat guns are now off the agenda.

 

I don't like having to pester about trivial stuff, I'd much rather post about the performance of my optics or some new apochromat, but thanks for helping.

[bosun21]

On 17/05/2023 at 13:42, Elp said:

Doesn't a splitter lower the amps going to each branch?

No, they will draw the required operating current as normal.