Torches - too much choice?

[LittleSkink]

I have been trying to use my 300 lumen NiteCore MT2A torch with a red filter and it just isn't really protecting my night vision very well, even on its minimum setting - though it is great for scaring away foxes!

Wonder if a head torch might be more convenient, but finding one that doesn't claim to be "super bright" is proving challenging

Stuff like this isn't expensive but is it any good for Astro work?

http://www.ebay.co.uk/itm/Night-storm-LED-Headlight-Hunting-Vision-Camping-Headlamp-Survival-Head-Torch-/291078914383?pt=LH_DefaultDomain_3&hash=item43c5a7c14f

For not much more money I can get a "proper" Astro torch like this

http://www.ebay.co.uk/itm/Celestron-Flashlight-Night-Vision-2-red-LED-Black-Astronomy-Torch-/321495488757?pt=LH_DefaultDomain_3&hash=item4ada9fd8f5

no doubt folks will offer even more choices . . .

[Qualia]

To retain night vision most astronomers recommend a red light but red light in itself does not equate to suitable for night vision.

Any light impacts on dark adaptation, but for the minimum impact, a very dim red is best. In my mind a decent astronomy light should start out dim with no chance of triggering any kind of white light by mistake and it should be able to go from that really dim light to truly dark adapted dim settings. In short, it's not just about having a red light; it's about having a very dim red light and then an even dimmer and dimmer red light.

Many astronomers find a red torch, or a white torch nail painted in red etc, suffice but I'm not in this camp. Even the little devices I have made for myself or which I have seen other folk use, have either been too bright or with very little chance of dimming them any further. Although I find it too bright on a higher setting, I'm thinking along the lines of the red light used in a Telrad or Quickfinder, where you set it to visible circles and you keep dimming them as the evening sky darkens. This dimming is handy, for while a certain amount of light is needed to read the fine detail of star charts, another is needed for night-time collimation, perhaps another for sketching and then another for looking for something that had been mislaid or dropped, and so on.

I've also found that this red light should not only be as dim as possible in each of the given situations encountered, but also diffuse enough so that there is no bright point-source of red light. By this, I mean that although the red torch light itself may appear dim, the actual light pumping out is at quite an intense wavelength. This may not seem a problem until for some reason or other, you accidently look at the torch end and a moment of singular brightness means that dark adaption is back to square one.

It does seem a ridiculous situation. One spends a good amount of cash on a nice scope, pricey eyepieces, and other astro-gear, one has carried themselves far to some dark site only to be limiting one's observing potential by a silly red light.

In my search for an ideal red light, I've found that although the most often used are in the  620 - 630 nm range of the visible spectrum, to achieve a truer night vision light, one ought to look for a 660 nm or greater, in the deep-red range of the visible spectrum.

When looking about I couldn’t find many favourable reviews of any of the more mainstream astronomy red lights on the market. Indeed, with a little searching you'll probably find few favourable reviews of the Skywatcher, Orion, or Celestron red lights.

I had almost given up my searchings when by accident I stumbled upon a tiny Spanish outlet selling a true deep red light made by Rigel Systems. This little torch called a Rigel Starlite has been one of my best accessory buys. It simply is better than any other torch I've ever used and better than any of the self-made torches. Sure, it’s a reasonably expensive item costing around €25 but I guess I’ve spent that already trying to modify my own red light experiments and at the end of the day, it seems a very small price to pay in terms of astro-gear when out alone at the extreme fringe of dso targets and trying to sketch them, or hunting them out on my star chart or tweaking the truss dob’s collimation at 3am in the morning.

You might also find this a handy link.