{"id":59144,"date":"2024-05-19T09:10:00","date_gmt":"2024-05-19T09:10:00","guid":{"rendered":"http:\/\/342fd55d-3433-4890-8323-51cce0d902f9"},"modified":"2024-05-19T10:08:27","modified_gmt":"2024-05-19T10:08:27","slug":"the-suns-activity-is-increasing-record-the-path-to-solar-maximum-with-our-guide-on-how-to-photograph-sunspots","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/the-suns-activity-is-increasing-record-the-path-to-solar-maximum-with-our-guide-on-how-to-photograph-sunspots\/","title":{"rendered":"The Sun’s activity is increasing. Record the path to solar maximum with our guide on how to photograph sunspots"},"content":{"rendered":"

<\/p>

By Pete Lawrence\n <\/p>

Published: Sunday, 19 May 2024 at 09:10 AM<\/p>

\n\n

Taking the time to photograph sunspots on a daily or near-daily schedule can become a fairly rapid process, and provides an important record of how solar activity is progressing.<\/p>

With the next solar maximum expected to occur in 2025, this is a great time to start imaging the Sun in white light.<\/p>

As ever, for your photograph of sunspots<\/a> to carry any scientific weight, it\u2019s key to record time, date, observer location and image orientation, along with details of the equipment used.<\/p>

And it needs to be pointed out that any equipment to be pointed at the Sun needs to be appropriately filtered first.<\/p>

Failure to heed this warning could lead to equipment damage and potentially damage to your eyesight.<\/p>

Read our guides on how to photograph the Sun<\/a> and how to photograph solar activity<\/a>.<\/em><\/strong><\/p>

Sunspot group in February 2024. Credit: Pete Lawrence<\/figcaption><\/figure>

Using filters to photograph sunspots<\/strong><\/h2>

The safest way to image the Sun and photograph sunspots in white light is to fit a white-light solar filter over the full aperture of the scope.<\/p>

Any attached finders need to be filtered, capped or removed for safety too.<\/p>

If you\u2019re using a large scope, an offset aperture filter can be used.<\/p>

This is achieved by covering the entire aperture with an opaque cover such as thick card.<\/p>

A smaller hole is created in the card and this is covered with filter material. <\/p>

\"How
Credit: Pete Lawrence<\/figcaption><\/figure>

As larger scopes tend to have secondary mirrors, the hole is offset to one side to avoid being blocked by the secondary.<\/p>

The most common type of filter material is Baader AstroSolar film, although there are several other types available too.<\/p>

AstroSolar film is available in A4 sheets or in larger rolls 0.5 x 1.0 metres in size, and reduces the incoming light sufficiently to allow the Sun to be viewed and imaged in much the same way as you would the Moon.<\/p>

Once the scope has been filtered, it can be turned to the Sun and imaging can take place.<\/p>

\"Sunspot
Sunspot Group on 02.04.17 by Amit Sharma, London, UK. Equipment: TS optics 60ED, Quark chromosphere, QHY 5L-II Mono<\/figcaption><\/figure>

Which camera to use<\/strong><\/h2>

The best type of camera for photographing sunspots will be a monochrome high-frame-rate camera.<\/p>

The reason for this is that a monochrome sensor will not suffer from the effects of atmospheric dispersion, where an object\u2019s light gets smeared into a rainbow of colour.<\/p>

The effect is worse with decreasing altitude, so with the Sun high in the sky it may not be that noticeable.<\/p>

As altitude lowers, however, dispersion starts to cause blurring and colour fringing for colour cameras.<\/p>

Actually, the same is true of monochrome cameras, but you can\u2019t see the colours.<\/p>

Here, the effect is easily reduced by using a single-colour imaging filter.<\/p>

Typically a green filter works best, as it picks out solar granulation better than other colours.<\/p>

Specialised solar continuum filters are also available for this.<\/p>

Of course, a filter could be used with a one-shot-colour camera as well, but this has the effect of reducing the camera\u2019s efficiency quite dramatically due to the Bayer colour filter matrix used on such cameras.\u00a0<\/p>

Once you\u2019re filtered and have your camera fitted, you\u2019re good to go.<\/p>

\"AR2553
AR2553 by Ewan Hobbs, UK. Equipment: AZEQ6 Mount, 152mm TecnoSky Refractor, 135mm Baader D-ERF Front Mounted Filter, Daystar Quark Chromosphere, DMK21AU618<\/figcaption><\/figure>

Equipment<\/strong><\/h2>