Advice needed for future purchases

[SyberJ94]

Hi all,
I have a 10"collapsible skywatcher dobsonian which I've had for a few years and have decided it is time to buy some filters and eyepieces for it. I like to look at all aspects of the night sky so any help on what brands and anything in general will be really helpful. Also what sites are the best when it comes to these things. Last thing as well should I try and get coloured solar filter or save and buy a dedicated solar scope?

Thank you all.

[Allan]

I will start by warning you to be very careful with solar viewing. Make sure you know what you are doing before attempting solar viewing because you can quickly destroy your vision if you get it wrong. On your Dob you can use a full aperture solar film filter that fits over the front of your tube. But you must be very careful there is no way for it to fall off or get knocked off while viewing the sun, or else instant eye damage. You can't use a filter that screws into the eyepiece to view the sun because the heat generated will almost instantly shatter the filter.

I do some white light solar observing with my refractor and that keeps me happy enough. I am not interested in buying a dedicated solar scope, but for those who really get into solar observing, using a Ha solar scope is really cool. I've viewed through them at star parties and they are pretty neat.

My suggestion though is to get help from someone with experience first, and try and observe through a solar scope before buying one, as they can be expensive and only useful for one object.

What sort of objects do you like observing? That will help determine which eyepieces and filters to recommend. As far as where to buy, I can highly recommend Bintel in Sydney. They are very helpful in the store. They could explain the whole solar observing thing to you so you could get started safely.

[AstralTraveller]

For solar viewing, as Allan says, you will always need a energy -rejection filter. In addition to this you can use other filters and I use a solar-continuum filter, which screws into the back of the eyepiece. It's green, which is the area of peak emission from the photosphere. It is no where near as good as a Ha scope and prominences are completely invisible but it does improve surface detail, especially around sunspots, compared to white-light viewing. They are also pretty cheap.

[SyberJ94]

Thanks for the responses, I currently have a makeshift solar filter for my dob but I just want to see more details. Plus I have used a ha scope a handful of times the last time was seeing the end of the transit of Venus so was seeing was there filters similar or would I need a specific scope. Also for what I like, it's normally the deeper objects like galaxies, nebula and things along those lines, but our own solar system is very fun to observe.

[Allan]

For seeing solar eclipses you only need a white light filter. The Ha scopes are more for seeing prominences and surface features. You can't see prominences in white light but at least you can see the sunspots and granulation on the surface. A Baader solar continuum filter does help bring out the surface detail using a white light filter as David said.

For deep sky, you might like to buy a narrow band filter to help show more contrast in a range of nebulae. I use the Lumicon UHC filter. Other good ones are the DGM NPB and Astronomics UHC. Another useful filter to get after the narrow band type is the OIII filter. It has a narrower bandpass which increases the contrast even further. They work better at larger exit pupils, so use your wider field eyepieces.

As for eyepieces, I use TeleVue and really like them. You can't go wrong with a good set of TeleVue's. There are so many choices out there now, and lots of info if you search old threads here or on Cloudy Nights. You will find many cheaper options that also do very well. A good bit of advice I pass on is, if you can only afford one expensive eyepiece, get a focal length that is twice your f/ratio. So for you, around 10mm. That will provide a nice exit pupil that will work for a vast number of objects. So maybe start there, and then get a longer focal length, around 24mm to 26mm, and then go from there filling in the gaps as you like.

[MattT]

Have you seen Alex's thread on the Daystar solar eyepiece?

http://www.iceinspace.com.au/forum/showthread.php?t=132375

Wouldn't mind one myself, but not at that price. Wouldn't mind a decent sized dedicated Solar scope….but not at the prices asked. Binoviewers give a much better white light image, combined with a Baader solar film for visual than a single eyepiece and cheaper than the Daystar or dedicated Solar scope. William Optics is what I have, cost $200 second hand 3 1/2 years ago….Baader film….cheap as chips.

As for eyepieces…as Brian says in Monty Python's movie 'Life of Brian'…. you have to work it out for yourself. Buy them and use them ...for months. Looking through an eyepiece once or twice isn't enough to know if you like it or not. Keep what you like, sell what you don't.

FWIW that is my approach.

Matt

[julianh72]

One thing that worries me when people use the terms "collapsible Dob" and "solar observation" in the same sentence:

Is it EVER truly safe to use an open-tube telescope for solar viewing, even with a full-aperture solar filter on the front?

Is there any risk that a dangerous amount of heat / light could be brought to focus if the telescope is knocked sightly off-axis, such that some sunlight can hit the primary mirror through the open side of the tube? At the very least, I would think it would be very desirable (essential?) to use some sort of 100% opaque "shroud" around the open part of the tube, to make sure there is no way direct sunlight can enter the optical path?

(I've never used an open telescope in daylight hours, so I don't know if I'm being overly dramatic, but I don't think you can EVER be too careful with the gift of sight!)