What is the Best Solar Telescope? That question is broad and ambiguous, there are many factors to consider before you make your financial investment. I have many years’ experience in this hobby and made my fair share of costly mistakes through the influence of others. What is right for one person may not be right for you.
Whether you already own a solar telescope, a nighttime telescope or just starting out this article will help.
What is a Solar Telescope? The shortest definition: any Telescope that allows you to SAFELY view the sun.
Types of Solar Telescopes: In this section, I will use the term category to describe each type. If you are not sure what each type of Solar Telescope offers, I suggest you Google each category and browse the images taken with these types of telescopes to give you an idea of what to expect.
White light: This is the least expensive and is an excellent starting point for those beginning the hobby. Even diehard enthusiasts will most always have a White Light set up. Assuming you already own a telescope all you need is a sheet of Solar Film large enough to make a front filter to cover the front of your telescope. The cost is around $30.00 depending on the diameter of your telescope. A more durable option is a glass white light filter. For higher quality and at a higher cost still ($200.00 – $700.00) and a safer option is a Solar Wedge that attaches to the rear of your telescope. I recommend you start with the Solar Film to determine if you have an interest in viewing sunspots, and that is pretty much all you will see with White Light is Sun Spots.
Calcium H or K: The difference between H and K is K-line is harder to see with the human eye and as you get older have a harder time making out details. The K-Line spectrum of light is very near the limits of human sight. H line is a little more forgiving for visuals. The cost associated with Calcium is around $1100.00. Both Lunt and Daystar offer Calcium Filters that attach to the rear of your existing telescope. Baader offers a 1.25” screw-in filter but that can ONLY be used for imaging. Calcium is used to view the emission lines from the chromosphere, slightly lower and cooler than Hydrogen-alpha. Both the H or K-line Calcium filter support imaging.
Sodium D: One of the less popular filters but still provides pleasing views of the Sun’s active regions of plague and granulations. Daystar offers this filter as a drop-in into your diagonal for around $1100.00 or a much more expensive in-line module starting at $5200.00.
Hydrogen-alpha: This is by far the more popular solar filter and is what most people gravitate to. HA telescopes and filters are available in a wide range of options and sizes to accommodate many budget levels. Most people will upgrade from White Light to HA due to the popularity, ease of use, availability to fit within many budgets, and the spectacular views HA provides.
How to determine the best telescope for you: Regardless of your choice for the type of Telescope you are interested in using, be it White Light, Calcium, Sodium, or HA. What matters most is the level of enjoyment you get from the hobby. Your enjoyment is most often determined by cost, ease of use aka Size, and Weight.
Cost: It is not all that fun going into debt for a hobby, and making your Solar investment should be a long-term decision. I recommend visiting a Star Party “post-COVID” and do plenty of research before making a large investment. You never get your investment back if you do an impulse buy then later try to sell the equipment.
Ease of Use: portability and Ease of Use should be seriously factored into your decision. Buying a large Solar Refactor which depends on a large amount will soon take its toll on your enjoyment and your back. Consider this: How long will it take to pack up, carry, unpack, and set up a large system? Sure, it looks impressive and provides great views. If your current system is 10 -30 pounds a large solar setup maybe a 100 pounds or more with the mount, counterweights, Head, OTA, and cases. Will it fit in your vehicle? If you don’t have experience with heavy Telescope setups, I recommend you find two 25-pound cinder blocks and carry them around for 20 minutes in the hot humid sun. Take my advice the easier it is to use and set up the more you will use and enjoy it. I am not saying don’t go big or go home, just carefully consider the long-term commitment – we all age.
Dedicated or Build your own? A dedicated solar telescope has a few benefits the most obvious is ready to go on a whim and is the safest to use. The downside depending on the brand might be it can only be used for Solar work and not at night. Lunt now offers Universal Day and Night telescopes which offers the best of both worlds. Remove the Solar end and replace it with the Night time end and you are ready to go when night falls.
Build your own: Many people go this route because they already have an investment in a Night Time Telescope. Many of these can be fitted with solar filters. Lunt, Daystar, and other companies offer several different filters to turn your Night time OTA into a Solar Telescope. Always check with the manufacture before purchasing to determine if your OTA is suited for the filter you are interested in and what other options will be needed, e.g., ERF, UV/IR filter, Masking Filter, etc.
Refactors offer the best choice and are the easiest to adapt. Refactors up to 100mm can be adapted without the need of an Energy Rejection Filter, once you go past a 100mm OTA the cost goes up as well. Some types of telescopes are NOT suited due to internal mirrors and design.
A concern with some refactors is the OTA and focuser are too long to achieve focus when using solar filters. Check the forums and use google to determine if others have successfully adopted your OTA brand into a solar telescope. Nothing more frustrating than finding out the hard way your OTA does not provide enough inward focus.
Advisory: Not all brands of Telescopes can fully support Solar. One major concern is the in-focus or back focus. The OTA and focuser are too long to achieve acquiring sharp focus visually or with a camera. I recommend you research your OTA first for adapting it to Solar.
Dedicated Filters vs Daystar: This is where a lot of arguments ensue, one camp vs the other camp. Both provide the enjoyment of Solar viewing and imaging they just go about it differently.
Daystar is an electronic solar filter that requires power and employs an internal precision heater to bring the filter into the band. These filters have adjustments for fine-tuning the views. Two concerns to consider, first these have an electronic component which can fail, and secondly, the filter relies on heat which in the summer can in some situations cause issues in acquiring fine-tuning – especially if the ambient temperature is high and the sun is shining on the filter. With that being said the daystar filters are a very good option with a moderate cost and offer big weight savings in the setup and ease of use. I personally own two and use them quite often.
Check with Daystar to determine if your particular telescope can be fitted.
A dedicated solar filter is just that so, there is not too much to “service” or be concerned with failing and these filters should last a very long time with proper care. Again, check with the manufacture to ensure your OTA is suited for the filter.
What is the best Solar Telescope? The one you took time and effort to research yourself. Best suited to your need is portable, easy to use, and provides you maximum enjoyment in the Solar hobby.